[DISCUSS] Flink SQL DDL Design

[Teja MVSR]

Hi all,

I have been following this thread and it looks interesting. Can I please be
of any help, please let me know.

Thanks,
Teja

On Wed, Dec 12, 2018, 4:31 AM Kurt Young <[hidden email] wrote:

> Sounds great, thanks for the effort, Shuyi.
>
> Best,
> Kurt
>
>
> On Wed, Dec 12, 2018 at 5:14 PM Shuyi Chen <[hidden email]> wrote:
>
> > Hi all,
> >
> > I summarize the MVP based on the features that we agreed upon. For table
> > update mode and custom watermark strategy and ts extractor, I found there
> > are some discussions, so I decided to leave them out for the MVP.
> > For row/map/array data type, I think we can add it as well if everyone
> > agrees.
> >
> >
> > 4) Event-Time Attributes and Watermarks
> > Cited from SQL Server 2017 document (
> >
> >
> https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2017
> > ),
> > "A
> > computed column is a virtual column that is not physically stored in the
> > table, unless the column is marked PERSISTED. A computed column
> expression
> > can use data from other columns to calculate a value for the column to
> > which it belongs. " I think we can also use introduce the PERSISTED
> keyword
> > for computed column to indicate that the field can be stored back to the
> > table, i.e. ts AS SYSTEMROWTIME() PERSISTED.
> >
> > 3) SOURCE / SINK / BOTH
> > GRANT/INVOKE sounds like a more standard option than adding a property to
> > CREATE TABLE to manage the ACL/permission. The ACL can be stored
> somewhere
> > in a database, and allow/disallow access to a dynamic table depending on
> > whether it's a "INSERT INTO" or "SELECT".
> >
> > I can volunteer to put the discussion as a FLIP.  I can try to summarize
> > the current discussion, and share edit permission with you to collaborate
> > on the documents. After we finalized the doc, we can publish it as a
> FLIP.
> > What do you think?
> >
> > Shuyi
> >
> >
> >
> > On Tue, Dec 11, 2018 at 9:13 AM Timo Walther <[hidden email]> wrote:
> >
> > > Hi all,
> > >
> > > thanks for summarizing the discussion @Shuyi. I think we need to
> include
> > > the "table update mode" problem as it might not be changed easily in
> the
> > > future. Regarding "support row/map/array data type", I don't see a
> > > problem why we should not support them now as the data types are
> already
> > > included in the runtime. The "support custom timestamp extractor" is
> > > solved by the computed columns approach. The "custom watermark
> strategy"
> > > can be added by supplying a class name as paramter in my opinion.
> > >
> > > Regarding the comments of Lin and Jark:
> > >
> > > @Lin: Instantiating a TableSource/Sink should not cost much, but we
> > > should not mix catalog discussion and DDL at this point.
> > >
> > > 4) Event-Time Attributes and Watermarks
> > > 4.b) Regarding `ts AS SYSTEMROWTIME()` and Lin's comment about "will
> > > violate the rule": there is no explicit rule of doing so. Computed
> > > column are also not standard compliant, if we can use information that
> > > is encoded in constraints we should use it. Adding more and more
> > > top-level properties makes the interaction with connectors more
> > > difficult. An additional HEADER keyword sounds too connector-specific
> > > and also not SQL compliant to me.
> > >
> > > 3) SOURCE / SINK / BOTH
> > > GRANT/INVOKE are mutating an existing table, right? In my opinion,
> > > independent of SQL databases but focusing on Flink user requirements, a
> > > CREATE TABLE statement should be an immutable definition of a
> connection
> > > to an external system.
> > >
> > > 7) Table Update Mode
> > > As far as I can see, the only thing missing for enabling all table
> modes
> > > is the declaration of a change flag. We could introduce a new keyword
> > > here similar to WATERMARK:
> > >
> > > CREATE TABLE output_kafka_t1(
> > >    id bigint,
> > >    msg varchar,
> > >    CHANGE_FLAG FOR isRetraction
> > > ) WITH (
> > >    type=kafka
> > >    ,...
> > > );
> > >
> > > CREATE TABLE output_kafka_t1(
> > >    CHANGE_FLAG FOR isUpsert
> > >    id bigint,
> > >    msg varchar,
> > >    PRIMARY_KEY(id)
> > > ) WITH (
> > >    type=kafka
> > >    ,...
> > > );
> > >
> > > What do you think?
> > >
> > > @Jark: We should definitely stage the discussions and mention the
> > > opinions and advantages/disadvantages that have been proposed already
> in
> > > the FLIP.
> > >
> > > Regards,
> > > Timo
> > >
> > > Am 10.12.18 um 08:10 schrieb Jark Wu:
> > > > Hi all,
> > > >
> > > > It's great to see we have an agreement on MVP.
> > > >
> > > > 4.b) Ingesting and writing timestamps to systems.
> > > > I would treat the field as a physical column not a virtual column. If
> > we
> > > > treat it as computed column, it will be confused that the behavior is
> > > > different when it is a source or sink.
> > > > When it is a physical column, the behavior could be unified. Then the
> > > > problem is how to mapping from the field to kafka message timestamp?
> > > > One is Lin proposed above and is also used in KSQL[1]. Another idea
> is
> > > > introducing a HEADER column which strictly map by name to the fields
> in
> > > > message header.
> > > > For example,
> > > >
> > > > CREATE TABLE output_kafka_t1(
> > > >    id bigint,
> > > >    ts timestamp HEADER,
> > > >    msg varchar
> > > > ) WITH (
> > > >    type=kafka
> > > >    ,...
> > > > );
> > > >
> > > > This is used in Alibaba but not included in the DDL draft. It will
> > > further
> > > > extend the SQL syntax, which is we should be cautious about. What do
> > you
> > > > think about this two solutions?
> > > >
> > > > 4.d) Custom watermark strategies:
> > > > @Timo,  I don't have a strong opinion on this.
> > > >
> > > > 3) SOURCE/SINK/BOTH
> > > > Agree with Lin, GRANT/INVOKE [SELECT|UPDATE] ON TABLE is a clean and
> > > > standard way to manage the permission, which is also adopted by
> HIVE[2]
> > > and
> > > > many databases.
> > > >
> > > > [1]:
> > https://docs.confluent.io/current/ksql/docs/tutorials/examples.html
> > > > [2]:
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=45876173#Hivedeprecatedauthorizationmode/LegacyMode-Grant/RevokePrivileges
> > > >
> > > > @Timo, it's great if someone can conclude the discussion and
> summarize
> > > into
> > > > a FLIP.
> > > > @Shuyi, Thanks a lot for putting it all together. The google doc
> looks
> > > good
> > > > to me, and I left some minor comments there.
> > > >
> > > > Regarding to the FLIP, I have some suggestions:
> > > > 1. The FLIP can contain MILESTONE1 and FUTURE WORKS.
> > > > 2. The MILESTONE1 is the MVP. It describes the MVP DDL syntax.
> > > > 3. Separate FUTURE WORKS into two parts: UNDER DISCUSSION and
> ADOPTED.
> > We
> > > > can derive MILESTONE2 from this easily when it is ready.
> > > >
> > > > I summarized the Future Works based on Shuyi's work:
> > > >
> > > > Adopted: (Should detailed described here...)
> > > > 1. support data type nullability and precision.
> > > > 2. comment on table and columns.
> > > >
> > > > Under Discussion: (Should briefly describe some options...)
> > > > 1. Ingesting and writing timestamps to systems.
> > > > 2. support custom watermark strategy.
> > > > 3. support table update mode
> > > > 4. support row/map/array data type
> > > > 5. support schema derivation
> > > > 6. support system versioned temporal table
> > > > 7. support table index
> > > >
> > > > We can continue the further discussion here, also can separate to an
> > > other
> > > > DISCUSS topic if it is a sophisticated problem such as Table Update
> > Mode,
> > > > Temporal Table.
> > > >
> > > > Best,
> > > > Jark
> > > >
> > > > On Mon, 10 Dec 2018 at 11:54, Lin Li <[hidden email]> wrote:
> > > >
> > > >> hi all,
> > > >> Thanks for your valuable input!
> > > >>
> > > >> 4) Event-Time Attributes and Watermarks:
> > > >> 4.b) @Fabian As you mentioned using a computed columns `ts AS
> > > >> SYSTEMROWTIME()`
> > > >> for writing out to kafka table sink will violate the rule that
> > computed
> > > >> fields are not emitted.
> > > >> Since the timestamp column in kafka's header area is a specific
> > > >> materialization protocol,
> > > >> why don't we treat it as an connector property? For an example:
> > > >> ```
> > > >> CREATE TABLE output_kafka_t1(
> > > >>    id bigint,
> > > >>    ts timestamp,
> > > >>    msg varchar
> > > >> ) WITH (
> > > >>    type=kafka,
> > > >>    header.timestamp=ts
> > > >>    ,...
> > > >> );
> > > >> ```
> > > >>
> > > >> 4d) For custom watermark strategies
> > > >> @Fabian Agree with you that opening another topic about this feature
> > > later.
> > > >>
> > > >> 3) SOURCE / SINK / BOTH
> > > >> I think the permissions and availabilities are two separately
> things,
> > > >> permissions
> > > >> can be managed well by using GRANT/INVOKE(you can call it DCL)
> > solutions
> > > >> which
> > > >> commonly used in different DBs. The permission part can be an new
> > topic
> > > for
> > > >> later discussion, what do you think?
> > > >>
> > > >> For the availabilities, @Fabian @Timo  I've another question,
> > > >> does instantiate a TableSource/Sink cost much or has some other
> > > downsides?
> > > >> IMO, create a new source/sink object via the construct seems not
> > costly.
> > > >> When receiving a DDL we should associate it with the catalog object
> > > >> (reusing an existence or create a new one).
> > > >> Am I lost something important?
> > > >>
> > > >> 5. Schema declaration:
> > > >> @Timo  yes, your concern about the user convenience is very
> important.
> > > But
> > > >> I haven't seen a clear way to solve this so far.
> > > >> Do we put it later and wait for more inputs from the community?
> > > >>
> > > >> Shuyi Chen <[hidden email]> 于2018年12月8日周六 下午4:27写道：
> > > >>
> > > >>> Hi all,
> > > >>>
> > > >>> Thanks a lot for the great discussion. I think we can continue the
> > > >>> discussion here while carving out a MVP so that the community can
> > start
> > > >>> working on. Based on the discussion so far, I try to summarize what
> > we
> > > >> will
> > > >>> do for the MVP:
> > > >>>
> > > >>> MVP
> > > >>>
> > > >>>     1. support CREATE TABLE
> > > >>>     2. support exisiting data type in Flink SQL, ignore nullability
> > and
> > > >>>     precision
> > > >>>     3. support table comments and column comments
> > > >>>     4. support table constraint PRIMARY KEY and UNIQUE
> > > >>>     5. support table properties using key-value pairs
> > > >>>     6. support partitioned by
> > > >>>     7. support computed column
> > > >>>     8. support from-field and from-source timestamp extractors
> > > >>>     9. support PERIODIC-ASCENDING, PERIODIC-BOUNDED, FROM-SOURCE
> > > watermark
> > > >>>     strategies.
> > > >>>     10. support a table property to allow explicit enforcement of
> > > >>>     read/write(source/sink) permission of a table
> > > >>>
> > > >>> I try to put up the DDL grammar (
> > > >>>
> > > >>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit?usp=sharing
> > > >>> )
> > > >>> based on the MVP features above and the previous design docs.
> Please
> > > >> take a
> > > >>> look and comment on it.
> > > >>>
> > > >>>
> > > >>> Also, I summarize the future Improvement on CREATE TABLE as the
> > > >> followings:
> > > >>>     1. support table update mode
> > > >>>     2. support data type nullability and precision
> > > >>>     3. support row/map/array data type
> > > >>>     4. support custom timestamp extractor and watermark strategy
> > > >>>     5. support schema derivation
> > > >>>     6. support system versioned temporal table
> > > >>>     7. support table index
> > > >>>
> > > >>> I suggest we first agree on the MVP feature list and the MVP
> grammar.
> > > And
> > > >>> then we can either continue the discussion of the future
> improvements
> > > >> here,
> > > >>> or create separate JIRAs for each item and discuss further in the
> > JIRA.
> > > >>> What do you guys think?
> > > >>>
> > > >>> Shuyi
> > > >>>
> > > >>> On Fri, Dec 7, 2018 at 7:54 AM Timo Walther <[hidden email]>
> > > wrote:
> > > >>>
> > > >>>> Hi all,
> > > >>>>
> > > >>>> I think we are making good progress. Thanks for all the feedback
> so
> > > >> far.
> > > >>>> 3. Sources/Sinks:
> > > >>>> It seems that I can not find supporters for explicit SOURCE/SINK
> > > >>>> declaration so I'm fine with not using those keywords.
> > > >>>> @Fabian: Maybe we don't haven have to change the TableFactory
> > > interface
> > > >>>> but just provide some helper functions in the TableFactoryService.
> > > This
> > > >>>> would solve the availability problem, but the permission problem
> > would
> > > >>>> still not be solved. If you are fine with it, we could introduce a
> > > >>>> property instead?
> > > >>>>
> > > >>>> 5. Schema declaration:
> > > >>>> @Lin: We should find an agreement on this as it requires changes
> to
> > > the
> > > >>>> TableFactory interface. We should minimize changes to this
> interface
> > > >>>> because it is user-facing. Especially, if format schema and table
> > > >> schema
> > > >>>> differ, the need for such a functionality is very important. Our
> > goal
> > > >> is
> > > >>>> to connect to existing infrastructure. For example, if we are
> using
> > > >> Avro
> > > >>>> and the existing Avro format has enums but Flink SQL does not
> > support
> > > >>>> enums, it would be helpful to let the Avro format derive a table
> > > >> schema.
> > > >>>> Otherwise your need to declare both schemas which leads to CREATE
> > > TABLE
> > > >>>> statements of 400 lines+.
> > > >>>> I think the mentioned query:
> > > >>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>>> format.schema-file = "/my/avrofile.avsc")
> > > >>>> is fine and should only be valid if the schema contains no
> > > non-computed
> > > >>>> columns.
> > > >>>>
> > > >>>> 7. Table Update Mode:
> > > >>>> After thinking about it again, I agree. The mode of the sinks can
> be
> > > >>>> derived from the query and the existence of a PRIMARY KEY
> > declaration.
> > > >>>> But Fabian raised a very good point. How do we deal with sources?
> > > Shall
> > > >>>> we introduce a new keywords similar to WATERMARKS such that a
> > > >>>> upsert/retract flag is not part of the visible schema?
> > > >>>>
> > > >>>> 4a. How to mark a field as attribute?
> > > >>>> @Jark: Thanks for the explanation of the WATERMARK clause
> semantics.
> > > >>>> This is a nice way of marking existing fields. This sounds good to
> > me.
> > > >>>>
> > > >>>> 4c) WATERMARK as constraint
> > > >>>> I'm fine with leaving the WATERMARK clause in the schema
> definition.
> > > >>>>
> > > >>>> 4d) Custom watermark strategies:
> > > >>>> I would already think about custom watermark strategies as the
> > current
> > > >>>> descriptor design already supports this. ScalarFunction's don't
> work
> > > as
> > > >>>> a PeriodicWatermarkAssigner has different semantics. Why not
> simply
> > > >>>> entering the a full class name here as it is done in the current
> > > >> design?
> > > >>>> 4.b) Ingesting and writing timestamps to systems (like Kafka)
> > > >>>> @Fabian: Yes, your suggestion sounds good to me. This behavior
> would
> > > be
> > > >>>> similar to our current `timestamps: from-source` design.
> > > >>>>
> > > >>>> Once our discussion has found a conclusion, I would like to
> > volunteer
> > > >>>> and summarize the outcome of this mailing thread. It nicely aligns
> > > with
> > > >>>> the update work on the connector improvements document (that I
> > wanted
> > > >> to
> > > >>>> do anyway) and the ongoing external catalog discussion.
> > Furthermore, I
> > > >>>> would also want to propose how to change existing interfaces by
> > > keeping
> > > >>>> the DDL, connector improvements, and external catalog support in
> > mind.
> > > >>>> Would that be ok for you?
> > > >>>>
> > > >>>> Thanks,
> > > >>>> Timo
> > > >>>>
> > > >>>>
> > > >>>>
> > > >>>> Am 07.12.18 um 14:48 schrieb Fabian Hueske:
> > > >>>>> Hi all,
> > > >>>>>
> > > >>>>> Thanks for the discussion.
> > > >>>>> I'd like to share my point of view as well.
> > > >>>>>
> > > >>>>> 4) Event-Time Attributes and Watermarks:
> > > >>>>> 4.a) I agree with Lin and Jark's proposal. Declaring a watermark
> on
> > > >> an
> > > >>>>> attribute declares it as an event-time attribute.
> > > >>>>> 4.b) Ingesting and writing timestamps to systems (like Kafka). We
> > > >> could
> > > >>>> use
> > > >>>>> a special function like (ts AS SYSTEMROWTIME()). This function
> will
> > > >>>>> indicate that we read the timestamp directly from the system (and
> > not
> > > >>> the
> > > >>>>> data). We can also write the field back to the system when
> emitting
> > > >> the
> > > >>>>> table (violating the rule that computed fields are not emitted).
> > > >>>>> 4c) I would treat WATERMARK similar to a PRIMARY KEY or UNIQUE
> KEY
> > > >>>>> constraint and therefore keep it in the schema definition.
> > > >>>>> 4d) For custom watermark strategies, a simple expressions or
> > > >>>>> ScalarFunctions won't be sufficient. Sophisticated approaches
> could
> > > >>>> collect
> > > >>>>> histograms, etc. But I think we can leave that out for later.
> > > >>>>>
> > > >>>>> 3) SOURCE / SINK / BOTH
> > > >>>>> As you said, there are two things to consider here: permission
> and
> > > >>>>> availability of a TableSource/TableSink.
> > > >>>>> I think that neither should be a reason to add a keyword at such
> a
> > > >>>>> sensitive position.
> > > >>>>> However, I also see Timo's point that it would be good to know
> > > >> up-front
> > > >>>> how
> > > >>>>> a table can be used without trying to instantiate a
> > TableSource/Sink
> > > >>> for
> > > >>>> a
> > > >>>>> query.
> > > >>>>> Maybe we can extend the TableFactory such that it provides
> > > >> information
> > > >>>>> about which sources/sinks it can provide.
> > > >>>>>
> > > >>>>> 7. Table Update Mode
> > > >>>>> Something that we definitely need to consider is how tables are
> > > >>> ingested,
> > > >>>>> i.e., append, retract or upsert.
> > > >>>>> Especially, since upsert and retraction need a meta-data column
> > that
> > > >>>>> indicates whether an event is an insert (or upsert) or a delete
> > > >> change.
> > > >>>>> This column needs to be identified somehow, most likely as part
> of
> > > >> the
> > > >>>>> input format. Ideally, this column should not be part of the
> table
> > > >>> schema
> > > >>>>> (as it would be always true).
> > > >>>>> Emitting tables is not so much of an issue as the properties of
> the
> > > >>> table
> > > >>>>> tell use what to do (append-only/update, unique key y/n).
> > > >>>>>
> > > >>>>> Best,
> > > >>>>> Fabian
> > > >>>>>
> > > >>>>>
> > > >>>>> Am Fr., 7. Dez. 2018 um 10:39 Uhr schrieb Jark Wu <
> > [hidden email]
> > > >>> :
> > > >>>>>> Hi Timo,
> > > >>>>>>
> > > >>>>>> Thanks for your quickly feedback! Here are some of my thoughts:
> > > >>>>>>
> > > >>>>>> Append, upserts, retract mode on sinks is also a very complex
> > > >>> problem. I
> > > >>>>>> think append/upserts/retract is the ability of a table, user do
> > not
> > > >>>> need to
> > > >>>>>> specify a table is used for append or retraction or upsert. The
> > > >> query
> > > >>>> can
> > > >>>>>> choose which mode the sink is. If an unbounded groupby is
> inserted
> > > >>> into
> > > >>>> an
> > > >>>>>> append sink (the sink only implements/supports append), an
> > exception
> > > >>>> can be
> > > >>>>>> thrown. A more complex problem is, if we want to write
> > > >>>> retractions/upserts
> > > >>>>>> to Kafka, how to encode the change flag (add or retract/delete)
> on
> > > >> the
> > > >>>>>> table? Maybe we should propose some protocal for the change flag
> > > >>>> encoding,
> > > >>>>>> but I don't have a clear idea about this right now.
> > > >>>>>>
> > > >>>>>> 3. Sources/Sinks: The source/sink tag is similar to the
> > > >>>>>> append/upsert/retract problem. Besides source/sink, actully we
> > have
> > > >>>> stream
> > > >>>>>> source, stream sink, batch source, batch sink, and the stream
> sink
> > > >>> also
> > > >>>>>> include append/upsert/retract three modes. Should we put all the
> > > >> tags
> > > >>> on
> > > >>>>>> the CREATE TABLE? IMO, the table's ability is defined by the
> table
> > > >>>> itself,
> > > >>>>>> user do not need to specify it. If it is only a readable table,
> an
> > > >>>>>> exception can be thrown when write to it. As the source/sink tag
> > can
> > > >>> be
> > > >>>>>> omitted in CREATE TABLE, could we skip it and only support
> CREATE
> > > >>> TABLE
> > > >>>> in
> > > >>>>>> the first version, and add it back in the future when we really
> > need
> > > >>>> it? It
> > > >>>>>> keeps API compatible and make sure the MVP is what we consider
> > > >>> clearly.
> > > >>>>>> 4a. How to mark a field as attribute?
> > > >>>>>> The watermark definition includes two parts: use which field as
> > time
> > > >>>>>> attribute and use what generate strategy.
> > > >>>>>> When we want to mark `ts` field as attribute: WATERMARK FOR `ts`
> > AS
> > > >>>> OFFSET
> > > >>>>>> '5' SECOND.
> > > >>>>>> If we have a POJO{id, user, ts} field named "pojo", we can mark
> it
> > > >>> like
> > > >>>>>> this: WATERMARK FOR pojo.ts AS OFFSET '5' SECOND
> > > >>>>>>
> > > >>>>>> 4b. timestamp write to Kafka message header
> > > >>>>>> Even though we can define multiple time attribute on a table,
> only
> > > >> one
> > > >>>> time
> > > >>>>>> attribute can be actived/used in a query (in a stream). When we
> > > >> enable
> > > >>>>>> `writeTiemstamp`, the only attribute actived in the stream will
> be
> > > >>>> write to
> > > >>>>>> Kafka message header. What I mean the timestmap in StreamRecord
> is
> > > >> the
> > > >>>> time
> > > >>>>>> attribute in the stream.
> > > >>>>>>
> > > >>>>>> 4c. Yes. We introduced the WATERMARK keyword similar to the
> INDEX,
> > > >>>> PRIMARY
> > > >>>>>> KEY keywords.
> > > >>>>>>
> > > >>>>>> @Timo, Do you have any other advice or questions on the
> watermark
> > > >>>> syntax ?
> > > >>>>>> For example, the builtin strategy name: "BOUNDED WITH OFFSET" VS
> > > >>>> "OFFSET"
> > > >>>>>> VS ...
> > > >>>>>>
> > > >>>>>>
> > > >>>>>> Cheers,
> > > >>>>>> Jark
> > > >>>>>>
> > > >>>>>> On Fri, 7 Dec 2018 at 17:13, Lin Li <[hidden email]>
> > wrote:
> > > >>>>>>
> > > >>>>>>> Hi Timo,
> > > >>>>>>> Thanks for your feedback, here's some thoughts of mine:
> > > >>>>>>>
> > > >>>>>>> 3. Sources/Sinks:
> > > >>>>>>> "Let's assume an interactive CLI session, people should be able
> > to
> > > >>> list
> > > >>>>>> all
> > > >>>>>>> source table and sink tables to know upfront if they can use an
> > > >>> INSERT
> > > >>>>>> INTO
> > > >>>>>>> here or not."
> > > >>>>>>> This requirement can be simply resolved by a document that list
> > all
> > > >>>>>>> supported source/sink/both connectors and the sql-client can
> > > >> perform
> > > >>> a
> > > >>>>>>> quick check. It's only an implementation choice, not necessary
> > for
> > > >>> the
> > > >>>>>>> syntax.
> > > >>>>>>> For connector implementation, a connector may implement one or
> > some
> > > >>> or
> > > >>>>>> all
> > > >>>>>>> of the [Stream|Batch]Source/[Stream|Batch]Sink traits, we can
> > > >> derive
> > > >>>> the
> > > >>>>>>> availability for any give query without the SOURCE/SINk
> keywords
> > or
> > > >>>>>>> specific table properties in WITH clause.
> > > >>>>>>> Since there's still indeterminacy, shall we skip these two
> > keywords
> > > >>> for
> > > >>>>>> the
> > > >>>>>>> MVP DDL? We can make further discussion after users' feedback.
> > > >>>>>>>
> > > >>>>>>> 6. Partitioning and keys
> > > >>>>>>> Agree with you that raise the priority of table constraint and
> > > >>>>>> partitioned
> > > >>>>>>> table support for better connectivity to Hive and Kafka. I'll
> add
> > > >>>>>>> partitioned table syntax(compatible to hive) into the DDL Draft
> > doc
> > > >>>>>>> later[1].
> > > >>>>>>>
> > > >>>>>>> 5. Schema declaration
> > > >>>>>>> "if users want to declare computed columns they have a "schema"
> > > >>>>>> constraints
> > > >>>>>>> but without columns
> > > >>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>>>>>> format.schema-file = "/my/avrofile.avsc") "
> > > >>>>>>>
> > > >>>>>>>   From the point of my view, this ddl is invalid because the
> > > primary
> > > >>> key
> > > >>>>>>> constraint already references two columns but types unseen.
> > > >>>>>>> And Xuefu pointed a important matching problem, so let's put
> > schema
> > > >>>>>>> derivation as a follow-up extension ?
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>> Timo Walther <[hidden email]> 于2018年12月6日周四 下午6:05写道：
> > > >>>>>>>
> > > >>>>>>>> Hi everyone,
> > > >>>>>>>>
> > > >>>>>>>> great to have such a lively discussion. My next batch of
> > feedback:
> > > >>>>>>>>
> > > >>>>>>>> @Jark: We don't need to align the descriptor approach with
> SQL.
> > > >> I'm
> > > >>>>>> open
> > > >>>>>>>> for different approaches as long as we can serve a broad set
> of
> > > >> use
> > > >>>>>>>> cases and systems. The descriptor approach was a first attempt
> > to
> > > >>>> cover
> > > >>>>>>>> all aspects and connector/format characteristics. Just another
> > > >>>> example,
> > > >>>>>>>> that is missing in the DDL design: How can a user decide if
> > > >> append,
> > > >>>>>>>> retraction, or upserts should be used to sink data into the
> > target
> > > >>>>>>>> system? Do we want to define all these improtant properties in
> > the
> > > >>> big
> > > >>>>>>>> WITH property map? If yes, we are already close to the
> > descriptor
> > > >>>>>>>> approach. Regarding the "standard way", most DDL languages
> have
> > > >> very
> > > >>>>>>>> custom syntax so there is not a real "standard".
> > > >>>>>>>>
> > > >>>>>>>> 3. Sources/Sinks: @Lin: If a table has both read/write access
> it
> > > >> can
> > > >>>> be
> > > >>>>>>>> created using a regular CREATE TABLE (omitting a specific
> > > >>> source/sink)
> > > >>>>>>>> declaration. Regarding the transition from source/sink to
> both,
> > > >> yes
> > > >>> we
> > > >>>>>>>> would need to update the a DDL and catalogs. But is this a
> > > >> problem?
> > > >>>> One
> > > >>>>>>>> also needs to add new queries that use the tables. @Xuefu: It
> is
> > > >> not
> > > >>>>>>>> only about security aspects. Especially for streaming use
> cases,
> > > >> not
> > > >>>>>>>> every connector can be used as a source easily. For example, a
> > > >> JDBC
> > > >>>>>> sink
> > > >>>>>>>> is easier than a JDBC source. Let's assume an interactive CLI
> > > >>> session,
> > > >>>>>>>> people should be able to list all source table and sink tables
> > to
> > > >>> know
> > > >>>>>>>> upfront if they can use an INSERT INTO here or not.
> > > >>>>>>>>
> > > >>>>>>>> 6. Partitioning and keys: @Lin: I would like to include this
> in
> > > >> the
> > > >>>>>>>> design given that Hive integration and Kafka key support are
> in
> > > >> the
> > > >>>>>>>> making/are on our roadmap for this release.
> > > >>>>>>>>
> > > >>>>>>>> 5. Schema declaration: @Lin: You are right it is not
> > conflicting.
> > > >> I
> > > >>>>>> just
> > > >>>>>>>> wanted to raise the point because if users want to declare
> > > >> computed
> > > >>>>>>>> columns they have a "schema" constraints but without columns.
> > Are
> > > >> we
> > > >>>> ok
> > > >>>>>>>> with a syntax like ...
> > > >>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>>>>>>> format.schema-file = "/my/avrofile.avsc") ?
> > > >>>>>>>> @Xuefu: Yes, you are right that an external schema might not
> > > >> excatly
> > > >>>>>>>> match but this is true for both directions:
> > > >>>>>>>> table schema "derives" format schema and format schema
> "derives"
> > > >>> table
> > > >>>>>>>> schema.
> > > >>>>>>>>
> > > >>>>>>>> 7. Hive compatibility: @Xuefu: I agree that Hive is popular
> but
> > we
> > > >>>>>>>> should not just adopt everything from Hive as there syntax is
> > very
> > > >>>>>>>> batch-specific. We should come up with a superset of
> historical
> > > >> and
> > > >>>>>>>> future requirements. Supporting Hive queries can be an
> > > >> intermediate
> > > >>>>>>>> layer on top of Flink's DDL.
> > > >>>>>>>>
> > > >>>>>>>> 4. Time attributes: @Lin: I'm fine with changing the
> > > >>>> TimestampExtractor
> > > >>>>>>>> interface as this is also important for better separation of
> > > >>> connector
> > > >>>>>>>> and table module [1]. However, I'm wondering about watermark
> > > >>>>>> generation.
> > > >>>>>>>> 4a. timestamps are in the schema twice:
> > > >>>>>>>> @Jark: "existing field is Long/Timestamp, we can just use it
> as
> > > >>>>>>>> rowtime": yes, but we need to mark a field as such an
> attribute.
> > > >> How
> > > >>>>>>>> does the syntax for marking look like? Also in case of
> > timestamps
> > > >>> that
> > > >>>>>>>> are nested in the schema?
> > > >>>>>>>>
> > > >>>>>>>> 4b. how can we write out a timestamp into the message header?:
> > > >>>>>>>> I agree to simply ignore computed columns when writing out.
> This
> > > >> is
> > > >>>>>> like
> > > >>>>>>>> 'field-change: add' that I mentioned in the improvements
> > document.
> > > >>>>>>>> @Jark: "then the timestmap in StreamRecord will be write to
> > Kafka
> > > >>>>>>>> message header": Unfortunately, there is no timestamp in the
> > > >> stream
> > > >>>>>>>> record. Additionally, multiple time attributes can be in a
> > schema.
> > > >>> So
> > > >>>>>> we
> > > >>>>>>>> need a constraint that tells the sink which column to use
> > > >> (possibly
> > > >>>>>>>> computed as well)?
> > > >>>>>>>>
> > > >>>>>>>> 4c. separate all time attribute concerns into a special clause
> > > >> next
> > > >>> to
> > > >>>>>>>> the regular schema?
> > > >>>>>>>> @Jark: I don't have a strong opinion on this. I just have the
> > > >>> feeling
> > > >>>>>>>> that the "schema part" becomes quite messy because the actual
> > > >> schema
> > > >>>>>>>> with types and fields is accompanied by so much metadata about
> > > >>>>>>>> timestamps, watermarks, keys,... and we would need to
> introduce
> > a
> > > >>> new
> > > >>>>>>>> WATERMARK keyword within a schema that was close to standard
> up
> > to
> > > >>>> this
> > > >>>>>>>> point.
> > > >>>>>>>>
> > > >>>>>>>> Thanks everyone,
> > > >>>>>>>> Timo
> > > >>>>>>>>
> > > >>>>>>>> [1] https://issues.apache.org/jira/browse/FLINK-9461
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>> Am 06.12.18 um 07:08 schrieb Jark Wu:
> > > >>>>>>>>> Hi Timo,
> > > >>>>>>>>>
> > > >>>>>>>>> Thank you for the valuable feedbacks.
> > > >>>>>>>>>
> > > >>>>>>>>> First of all, I think we don't need to align the SQL
> > > >> functionality
> > > >>> to
> > > >>>>>>>>> Descriptor. Because SQL is a more standard API, we should be
> as
> > > >>>>>>> cautious
> > > >>>>>>>> as
> > > >>>>>>>>> possible to extend the SQL syntax. If something can be done
> in
> > a
> > > >>>>>>> standard
> > > >>>>>>>>> way, we shouldn't introduce something new.
> > > >>>>>>>>>
> > > >>>>>>>>> Here are some of my thoughts:
> > > >>>>>>>>>
> > > >>>>>>>>> 1. Scope: Agree.
> > > >>>>>>>>> 2. Constraints: Agree.
> > > >>>>>>>>> 4. Time attributes:
> > > >>>>>>>>>      4a. timestamps are in the schema twice.
> > > >>>>>>>>>       If an existing field is Long/Timestamp, we can just use
> > it
> > > >> as
> > > >>>>>>>> rowtime,
> > > >>>>>>>>> no twice defined. If it is not a Long/Timestamp, we use
> > computed
> > > >>>>>> column
> > > >>>>>>>> to
> > > >>>>>>>>> get an expected timestamp column to be rowtime, is this what
> > you
> > > >>> mean
> > > >>>>>>>>> defined twice?  But I don't think it is a problem, but an
> > > >>> advantages,
> > > >>>>>>>>> because it is easy to use, user do not need to consider
> whether
> > > >> to
> > > >>>>>>>> "replace
> > > >>>>>>>>> the existing column" or "add a new column", he will not be
> > > >> confused
> > > >>>>>>>> what's
> > > >>>>>>>>> the real schema is, what's the index of rowtime in the
> schema?
> > > >>>>>>> Regarding
> > > >>>>>>>> to
> > > >>>>>>>>> the optimization, even if timestamps are in schema twice,
> when
> > > >> the
> > > >>>>>>>> original
> > > >>>>>>>>> timestamp is never used in query, then the projection
> pushdown
> > > >>>>>>>> optimization
> > > >>>>>>>>> can cut this field as early as possible, which is exactly the
> > > >> same
> > > >>> as
> > > >>>>>>>>> "replacing the existing column" in runtime.
> > > >>>>>>>>>
> > > >>>>>>>>>       4b. how can we write out a timestamp into the message
> > > >> header?
> > > >>>>>>>>>        That's a good point. I think computed column is just a
> > > >>> virtual
> > > >>>>>>>> column
> > > >>>>>>>>> on table which is only relative to reading. If we want to
> write
> > > >> to
> > > >>> a
> > > >>>>>>>> table
> > > >>>>>>>>> with computed column defined, we only need to provide the
> > columns
> > > >>>>>>> except
> > > >>>>>>>>> computed columns (see SQL Server [1]). The computed column is
> > > >>> ignored
> > > >>>>>>> in
> > > >>>>>>>>> the insert statement. Get back to the question, how can we
> > write
> > > >>> out
> > > >>>>>> a
> > > >>>>>>>>> timestamp into the message header? IMO, we can provide a
> > > >>>>>> configuration
> > > >>>>>>> to
> > > >>>>>>>>> support this, such as `kafka.writeTimestamp=true`, then the
> > > >>> timestmap
> > > >>>>>>> in
> > > >>>>>>>>> StreamRecord will be write to Kafka message header. What do
> you
> > > >>>>>> think?
> > > >>>>>>>>>        4c. separate all time attribute concerns into a
> special
> > > >>> clause
> > > >>>>>>> next
> > > >>>>>>>> to
> > > >>>>>>>>> the regular schema?
> > > >>>>>>>>>        Separating watermark into a special clause similar to
> > > >>>>>> PARTITIONED
> > > >>>>>>>> BY is
> > > >>>>>>>>> also a good idea. Conceptually, it's fine to put watermark in
> > > >>> schema
> > > >>>>>>> part
> > > >>>>>>>>> or out schema part. But if we want to support multiple
> > watermark
> > > >>>>>>>>> definition, maybe it would be better to put it in schema
> part.
> > It
> > > >>> is
> > > >>>>>>>>> similar to Index Definition that we can define several
> indexes
> > > >> on a
> > > >>>>>>> table
> > > >>>>>>>>> in schema part.
> > > >>>>>>>>>
> > > >>>>>>>>>        4d. How can people come up with a custom watermark
> > > >> strategy?
> > > >>>>>>>>>        In most cases, the built-in strategy can works good.
> If
> > we
> > > >>> need
> > > >>>>>> a
> > > >>>>>>>>> custom one, we can use a scalar function which restrict to
> only
> > > >>>>>> return
> > > >>>>>>> a
> > > >>>>>>>>> nullable Long, and use it in SQL like: WATERMARK for rowtime
> AS
> > > >>>>>>>>> watermarkUdf(a, b, c). The `watermarkUdf` is a user-defined
> > > >> scalar
> > > >>>>>>>> function
> > > >>>>>>>>> accepts 3 parameters and return a nullable Long which can be
> > used
> > > >>> as
> > > >>>>>>>>> punctuated watermark assigner. Another choice is
> implementing a
> > > >>> class
> > > >>>>>>>>> extending the
> > > >>>>>>>>>
> `org.apache.flink.table.sources.wmstrategies.WatermarkStrategy`
> > > >> and
> > > >>>>>> use
> > > >>>>>>>> it
> > > >>>>>>>>> in SQL: WATERMARK for rowtime AS
> 'com.my.MyWatermarkStrategy'.
> > > >> But
> > > >>> if
> > > >>>>>>>>> scalar function can cover the requirements here, I would
> prefer
> > > >> it
> > > >>>>>>> here,
> > > >>>>>>>>> because it keeps standard compliant. BTW, this feature is not
> > in
> > > >>> MVP,
> > > >>>>>>> we
> > > >>>>>>>>> can discuss it more depth in the future when we need it.
> > > >>>>>>>>>
> > > >>>>>>>>> 5. Schema declaration:
> > > >>>>>>>>> I like the proposal to omit the schema if we can get the
> schema
> > > >>> from
> > > >>>>>>>>> external storage or something schema file. Actually, we have
> > > >>> already
> > > >>>>>>>>> encountered this requirement in out company.
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>> +1 to @Xuefu that we should be as close as possible to Hive
> > > >> syntax
> > > >>>>>>> while
> > > >>>>>>>>> keeping SQL ANSI standard. This will make it more acceptable
> > and
> > > >>>>>> reduce
> > > >>>>>>>> the
> > > >>>>>>>>> learning cost for user.
> > > >>>>>>>>>
> > > >>>>>>>>> [1]:
> > > >>>>>>>>>
> > > >>
> > >
> >
> https://docs.microsoft.com/en-us/sql/relational-databases/partitions/create-partitioned-tables-and-indexes?view=sql-server-2017
> > > >>>>>>>>> Best,
> > > >>>>>>>>> Jark
> > > >>>>>>>>>
> > > >>>>>>>>> On Thu, 6 Dec 2018 at 12:09, Zhang, Xuefu <
> > > >> [hidden email]
> > > >>>>>>>> wrote:
> > > >>>>>>>>>> Hi Timo/Shuyi/Lin,
> > > >>>>>>>>>>
> > > >>>>>>>>>> Thanks for the discussions. It seems that we are converging
> to
> > > >>>>>>> something
> > > >>>>>>>>>> meaningful. Here are some of my thoughts:
> > > >>>>>>>>>>
> > > >>>>>>>>>> 1. +1 on MVP DDL
> > > >>>>>>>>>> 3. Markers for source or sink seem more about permissions on
> > > >>> tables
> > > >>>>>>> that
> > > >>>>>>>>>> belong to a security component. Unless the table is created
> > > >>>>>>> differently
> > > >>>>>>>>>> based on source, sink, or both, it doesn't seem necessary to
> > use
> > > >>>>>> these
> > > >>>>>>>>>> keywords to enforce permissions.
> > > >>>>>>>>>> 5. It might be okay if schema declaration is always needed.
> > > >> While
> > > >>>>>>> there
> > > >>>>>>>>>> might be some duplication sometimes, it's not always true.
> For
> > > >>>>>>> example,
> > > >>>>>>>>>> external schema may not be exactly matching Flink schema.
> For
> > > >>>>>>> instance,
> > > >>>>>>>>>> data types. Even if so, perfect match is not required. For
> > > >>> instance,
> > > >>>>>>> the
> > > >>>>>>>>>> external schema file may evolve while table schema in Flink
> > may
> > > >>> stay
> > > >>>>>>>>>> unchanged. A responsible reader should be able to scan the
> > file
> > > >>>>>> based
> > > >>>>>>> on
> > > >>>>>>>>>> file schema and return the data based on table schema.
> > > >>>>>>>>>>
> > > >>>>>>>>>> Other aspects:
> > > >>>>>>>>>>
> > > >>>>>>>>>> 7. Hive compatibility. Since Flink SQL will soon be able to
> > > >>> operate
> > > >>>>>> on
> > > >>>>>>>>>> Hive metadata and data, it's an add-on benefit if we can be
> > > >>>>>> compatible
> > > >>>>>>>> with
> > > >>>>>>>>>> Hive syntax/semantics while following ANSI standard. At
> least
> > we
> > > >>>>>>> should
> > > >>>>>>>> be
> > > >>>>>>>>>> as close as possible. Hive DDL can found at
> > > >>>>>>>>>>
> > > >>>
> https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL
> > > >>>>>>>>>> Thanks,
> > > >>>>>>>>>> Xuefu
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >> ------------------------------------------------------------------
> > > >>>>>>>>>> Sender:Lin Li <[hidden email]>
> > > >>>>>>>>>> Sent at:2018 Dec 6 (Thu) 10:49
> > > >>>>>>>>>> Recipient:dev <[hidden email]>
> > > >>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> > > >>>>>>>>>>
> > > >>>>>>>>>> Hi Timo and Shuyi,
> > > >>>>>>>>>>      thanks for your feedback.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 1. Scope
> > > >>>>>>>>>> agree with you we should focus on the MVP DDL first.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 2. Constraints
> > > >>>>>>>>>> yes, this can be a follow-up issue.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 3. Sources/Sinks
> > > >>>>>>>>>> If a TABLE has both read/write access requirements, should
> we
> > > >>>>>> declare
> > > >>>>>>> it
> > > >>>>>>>>>> using
> > > >>>>>>>>>> `CREATE [SOURCE_SINK|BOTH] TABLE tableName ...` ? A further
> > > >>>>>> question,
> > > >>>>>>>> if a
> > > >>>>>>>>>> TABLE
> > > >>>>>>>>>> t1 firstly declared as read only (as a source table), then
> for
> > > >>> some
> > > >>>>>>> new
> > > >>>>>>>>>> requirements
> > > >>>>>>>>>> t1 will change to a sink table,  in this case we need
> updating
> > > >>> both
> > > >>>>>>> the
> > > >>>>>>>> DDL
> > > >>>>>>>>>> and catalogs.
> > > >>>>>>>>>> Further more, let's think about the BATCH query, update one
> > > >> table
> > > >>>>>>>> in-place
> > > >>>>>>>>>> can be a common case.
> > > >>>>>>>>>> e.g.,
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> CREATE TABLE t1 (
> > > >>>>>>>>>>      col1 varchar,
> > > >>>>>>>>>>      col2 int,
> > > >>>>>>>>>>      col3 varchar
> > > >>>>>>>>>>      ...
> > > >>>>>>>>>> );
> > > >>>>>>>>>>
> > > >>>>>>>>>> INSERT [OVERWRITE] TABLE t1
> > > >>>>>>>>>> AS
> > > >>>>>>>>>> SELECT
> > > >>>>>>>>>>      (some computing ...)
> > > >>>>>>>>>> FROM t1;
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> So, let's forget these SOURCE/SINK keywords in DDL. For the
> > > >>>>>> validation
> > > >>>>>>>>>> purpose, we can find out other ways.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 4. Time attributes
> > > >>>>>>>>>> As Shuyi mentioned before, there exists an
> > > >>>>>>>>>>
> > `org.apache.flink.table.sources.tsextractors.TimestampExtractor`
> > > >>> for
> > > >>>>>>>> custom
> > > >>>>>>>>>> defined time attributes usage, but this expression based
> class
> > > >> is
> > > >>>>>> more
> > > >>>>>>>>>> friendly for table api not the SQL.
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> /**
> > > >>>>>>>>>>      * Provides the an expression to extract the timestamp
> > for a
> > > >>>>>> rowtime
> > > >>>>>>>>>> attribute.
> > > >>>>>>>>>>      */
> > > >>>>>>>>>> abstract class TimestampExtractor extends
> FieldComputer[Long]
> > > >> with
> > > >>>>>>>>>> Serializable {
> > > >>>>>>>>>>
> > > >>>>>>>>>>      /** Timestamp extractors compute the timestamp as Long.
> > */
> > > >>>>>>>>>>      override def getReturnType: TypeInformation[Long] =
> > > >>>>>>>>>> Types.LONG.asInstanceOf[TypeInformation[Long]]
> > > >>>>>>>>>> }
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> BTW, I think both the Scalar function and the
> > TimestampExtractor
> > > >>> are
> > > >>>>>>>>>> expressing computing logic, the TimestampExtractor has no
> more
> > > >>>>>>>> advantage in
> > > >>>>>>>>>> SQL scenarios.
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>> 6. Partitioning and keys
> > > >>>>>>>>>> Primary Key is included in Constraint part, and partitioned
> > > >> table
> > > >>>>>>>> support
> > > >>>>>>>>>> can be another topic later.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 5. Schema declaration
> > > >>>>>>>>>> Agree with you that we can do better schema derivation for
> > user
> > > >>>>>>>>>> convenience, but this is not conflict with the syntax.
> > > >>>>>>>>>> Table properties can carry any useful informations both for
> > the
> > > >>>>>> users
> > > >>>>>>>> and
> > > >>>>>>>>>> the framework, I like your `contract name` proposal,
> > > >>>>>>>>>> e.g., `WITH (format.type = avro)`, the framework can
> recognize
> > > >>> some
> > > >>>>>>>>>> `contract name` like `format.type`, `connector.type` and
> etc.
> > > >>>>>>>>>> And also derive the table schema from an existing schema
> file
> > > >> can
> > > >>> be
> > > >>>>>>>> handy
> > > >>>>>>>>>> especially one with too many table columns.
> > > >>>>>>>>>>
> > > >>>>>>>>>> Regards,
> > > >>>>>>>>>> Lin
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>> Timo Walther <[hidden email]> 于2018年12月5日周三 下午10:40写道：
> > > >>>>>>>>>>
> > > >>>>>>>>>>> Hi Jark and Shuyi,
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> thanks for pushing the DDL efforts forward. I agree that we
> > > >>> should
> > > >>>>>>> aim
> > > >>>>>>>>>>> to combine both Shuyi's design and your design.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> Here are a couple of concerns that I think we should
> address
> > in
> > > >>> the
> > > >>>>>>>>>> design:
> > > >>>>>>>>>>> 1. Scope: Let's focuses on a MVP DDL for CREATE TABLE
> > > >> statements
> > > >>>>>>> first.
> > > >>>>>>>>>>> I think this topic has already enough potential for long
> > > >>>>>> discussions
> > > >>>>>>>> and
> > > >>>>>>>>>>> is very helpful for users. We can discuss CREATE VIEW and
> > > >> CREATE
> > > >>>>>>>>>>> FUNCTION afterwards as they are not related to each other.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 2. Constraints: I think we should consider things like
> > > >>> nullability,
> > > >>>>>>>>>>> VARCHAR length, and decimal scale and precision in the
> future
> > > >> as
> > > >>>>>> they
> > > >>>>>>>>>>> allow for nice optimizations. However, since both the
> > > >> translation
> > > >>>>>> and
> > > >>>>>>>>>>> runtime operators do not support those features. I would
> not
> > > >>>>>>> introduce
> > > >>>>>>>> a
> > > >>>>>>>>>>> arbitrary default value but omit those parameters for now.
> > This
> > > >>> can
> > > >>>>>>> be
> > > >>>>>>>> a
> > > >>>>>>>>>>> follow-up issue once the basic DDL has been merged.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 3. Sources/Sinks: We had a discussion about CREATE TABLE vs
> > > >>> CREATE
> > > >>>>>>>>>>> [SOURCE|SINK|] TABLE before. In my opinion we should allow
> > for
> > > >>>>>> these
> > > >>>>>>>>>>> explicit declaration because in most production scenarios,
> > > >> teams
> > > >>>>>> have
> > > >>>>>>>>>>> strict read/write access requirements. For example, a data
> > > >>> science
> > > >>>>>>> team
> > > >>>>>>>>>>> should only consume from a event Kafka topic but should not
> > > >>>>>>> accidently
> > > >>>>>>>>>>> write back to the single source of truth.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 4. Time attributes: In general, I like your computed
> columns
> > > >>>>>> approach
> > > >>>>>>>>>>> because it makes defining a rowtime attributes transparent
> > and
> > > >>>>>>> simple.
> > > >>>>>>>>>>> However, there are downsides that we should discuss.
> > > >>>>>>>>>>> 4a. Jarks current design means that timestamps are in the
> > > >> schema
> > > >>>>>>> twice.
> > > >>>>>>>>>>> The design that is mentioned in [1] makes this more
> flexible
> > as
> > > >>> it
> > > >>>>>>>>>>> either allows to replace an existing column or add a
> computed
> > > >>>>>> column.
> > > >>>>>>>>>>> 4b. We need to consider the zoo of storage systems that is
> > out
> > > >>>>>> there
> > > >>>>>>>>>>> right now. Take Kafka as an example, how can we write out a
> > > >>>>>> timestamp
> > > >>>>>>>>>>> into the message header? We need to think of a reverse
> > > >> operation
> > > >>>>>> to a
> > > >>>>>>>>>>> computed column.
> > > >>>>>>>>>>> 4c. Does defining a watermark really fit into the schema
> part
> > > >> of
> > > >>> a
> > > >>>>>>>>>>> table? Shouldn't we separate all time attribute concerns
> > into a
> > > >>>>>>> special
> > > >>>>>>>>>>> clause next to the regular schema, similar how PARTITIONED
> BY
> > > >>> does
> > > >>>>>> it
> > > >>>>>>>> in
> > > >>>>>>>>>>> Hive?
> > > >>>>>>>>>>> 4d. How can people come up with a custom watermark
> strategy?
> > I
> > > >>>>>> guess
> > > >>>>>>>>>>> this can not be implemented in a scalar function and would
> > > >>> require
> > > >>>>>>> some
> > > >>>>>>>>>>> new type of UDF?
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 6. Partitioning and keys: Another question that the DDL
> > design
> > > >>>>>> should
> > > >>>>>>>>>>> answer is how do we express primary keys (for upserts),
> > > >>>>>> partitioning
> > > >>>>>>>>>>> keys (for Hive, Kafka message keys). All part of the table
> > > >>> schema?
> > > >>>>>>>>>>> 5. Schema declaration: I find it very annoying that we want
> > to
> > > >>>>>> force
> > > >>>>>>>>>>> people to declare all columns and types again even though
> > this
> > > >> is
> > > >>>>>>>>>>> usually already defined in some company-wide format. I know
> > > >> that
> > > >>>>>>>> catalog
> > > >>>>>>>>>>> support will greatly improve this. But if no catalog is
> used,
> > > >>>>>> people
> > > >>>>>>>>>>> need to manually define a schema with 50+ fields in a Flink
> > > >> DDL.
> > > >>>>>>> What I
> > > >>>>>>>>>>> actually promoted having two ways of reading data:
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 1. Either the format derives its schema from the table
> > schema.
> > > >>>>>>>>>>> CREATE TABLE (col INT) WITH (format.type = avro)
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 2. Or the table schema can be omitted and the format schema
> > > >>> defines
> > > >>>>>>> the
> > > >>>>>>>>>>> table schema (+ time attributes).
> > > >>>>>>>>>>> CREATE TABLE WITH (format.type = avro, format.schema-file =
> > > >>>>>>>>>>> "/my/avrofile.avsc")
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> Please let me know what you think about each item. I will
> try
> > > >> to
> > > >>>>>>>>>>> incorporate your feedback in [1] this week.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> Regards,
> > > >>>>>>>>>>> Timo
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> [1]
> > > >>>>>>>>>>>
> > > >>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit#heading=h.41fd6rs7b3cf
> > > >>>>>>>>>>> Am 05.12.18 um 13:01 schrieb Jark Wu:
> > > >>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> It's exciting to see we can make such a great progress
> here.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> Regarding to the watermark:
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> Watermarks can be defined on any columns (including
> > > >>>>>> computed-column)
> > > >>>>>>>> in
> > > >>>>>>>>>>>> table schema.
> > > >>>>>>>>>>>> The computed column can be computed from existing columns
> > > >> using
> > > >>>>>>>> builtin
> > > >>>>>>>>>>>> functions and *UserDefinedFunctions* (ScalarFunction).
> > > >>>>>>>>>>>> So IMO, it can work out for almost all the scenarios not
> > only
> > > >>>>>> common
> > > >>>>>>>>>>>> scenarios.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> I don't think using a `TimestampExtractor` to support
> custom
> > > >>>>>>> timestamp
> > > >>>>>>>>>>>> extractor in SQL is a good idea. Because
> > `TimestampExtractor`
> > > >>>>>>>>>>>> is not a SQL standard function. If we support
> > > >>> `TimestampExtractor`
> > > >>>>>>> in
> > > >>>>>>>>>>> SQL,
> > > >>>>>>>>>>>> do we need to support CREATE FUNCTION for
> > > >> `TimestampExtractor`?
> > > >>>>>>>>>>>> I think `ScalarFunction` can do the same thing with
> > > >>>>>>>>>> `TimestampExtractor`
> > > >>>>>>>>>>>> but more powerful and standard.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> The core idea of the watermark definition syntax is that
> the
> > > >>>>>> schema
> > > >>>>>>>>>> part
> > > >>>>>>>>>>>> defines all the columns of the table, it is exactly what
> the
> > > >>> query
> > > >>>>>>>>>> sees.
> > > >>>>>>>>>>>> The watermark part is something like a primary key
> > definition
> > > >> or
> > > >>>>>>>>>>> constraint
> > > >>>>>>>>>>>> on SQL Table, it has no side effect on the schema, only
> > > >> defines
> > > >>>>>> what
> > > >>>>>>>>>>>> watermark strategy is and makes which field as the rowtime
> > > >>>>>> attribute
> > > >>>>>>>>>>> field.
> > > >>>>>>>>>>>> If the rowtime field is not in the existing fields, we can
> > use
> > > >>>>>>>> computed
> > > >>>>>>>>>>>> column
> > > >>>>>>>>>>>> to generate it from other existing fields. The Descriptor
> > > >>> Pattern
> > > >>>>>>> API
> > > >>>>>>>>>> [1]
> > > >>>>>>>>>>>> is very useful when writing a Table API job, but is not
> > > >>>>>>> contradictory
> > > >>>>>>>>>> to
> > > >>>>>>>>>>>> the
> > > >>>>>>>>>>>> Watermark DDL from my perspective.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> [1]:
> > > >>>>>>>>>>>>
> > > >>
> > >
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > > >>>>>>>>>>>> .
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> Best,
> > > >>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> On Wed, 5 Dec 2018 at 17:58, Shuyi Chen <
> [hidden email]
> > >
> > > >>>>>> wrote:
> > > >>>>>>>>>>>>> Hi Jark and Shaoxuan,
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> Thanks a lot for the summary. I think we are making great
> > > >>>>>> progress
> > > >>>>>>>>>> here.
> > > >>>>>>>>>>>>> Below are my thoughts.
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> *(1) watermark definition
> > > >>>>>>>>>>>>> IMO, it's better to keep it consistent with the rowtime
> > > >>>>>> extractors
> > > >>>>>>>> and
> > > >>>>>>>>>>>>> watermark strategies defined in
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>>
> > > >>
> > >
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > > >>>>>>>>>>>>> .
> > > >>>>>>>>>>>>> Using built-in functions seems to be too much for most of
> > the
> > > >>>>>>> common
> > > >>>>>>>>>>>>> scenarios.
> > > >>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > > >>>>>>>>>>>>> Actually, I think we can put the source/sink type info
> into
> > > >> the
> > > >>>>>>> table
> > > >>>>>>>>>>>>> properties, so we can use CREATE TABLE.
> > > >>>>>>>>>>>>> (3) View DDL with properties
> > > >>>>>>>>>>>>> We can remove the view properties section now for the MVP
> > and
> > > >>> add
> > > >>>>>>> it
> > > >>>>>>>>>>> back
> > > >>>>>>>>>>>>> later if needed.
> > > >>>>>>>>>>>>> (4) Type Definition
> > > >>>>>>>>>>>>> I agree we can put the type length or precision into
> future
> > > >>>>>>> versions.
> > > >>>>>>>>>> As
> > > >>>>>>>>>>>>> for the grammar difference, currently, I am using the
> > grammar
> > > >>> in
> > > >>>>>>>>>> Calcite
> > > >>>>>>>>>>>>> type DDL, but since we'll extend the parser in Flink, so
> we
> > > >> can
> > > >>>>>>>>>>> definitely
> > > >>>>>>>>>>>>> change if needed.
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> On Tue, Dec 4, 2018 at 10:48 PM Jark Wu <
> [hidden email]>
> > > >>>>>> wrote:
> > > >>>>>>>>>>>>>> Hi Shaoxuan,
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> Thanks for pointing that out. Yes, the source/sink tag
> on
> > > >>> create
> > > >>>>>>>>>> table
> > > >>>>>>>>>>> is
> > > >>>>>>>>>>>>>> the another major difference.
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> Summarize the main differences again:
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> *(1) watermark definition
> > > >>>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > > >>>>>>>>>>>>>> (3) View DDL with properties
> > > >>>>>>>>>>>>>> (4) Type Definition
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> Best,
> > > >>>>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> On Wed, 5 Dec 2018 at 14:08, Shaoxuan Wang <
> > > >>> [hidden email]
> > > >>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>> Hi Jark,
> > > >>>>>>>>>>>>>>> Thanks for the summary. Your plan for the 1st round
> > > >>>>>>> implementation
> > > >>>>>>>>>> of
> > > >>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>> looks good to me.
> > > >>>>>>>>>>>>>>> Have we reached the agreement on simplifying/unifying
> > > >> "create
> > > >>>>>>>>>>>>>> [source/sink]
> > > >>>>>>>>>>>>>>> table" to "create table"? "Watermark definition" and
> > > >> "create
> > > >>>>>>> table"
> > > >>>>>>>>>>> are
> > > >>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>> major obstacles on the way to merge two design
> proposals
> > > >>> FMPOV.
> > > >>>>>>>>>>> @Shuyi,
> > > >>>>>>>>>>>>>> It
> > > >>>>>>>>>>>>>>> would be great if you can spend time and respond to
> these
> > > >> two
> > > >>>>>>> parts
> > > >>>>>>>>>>>>>> first.
> > > >>>>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>>>> Shaoxuan
> > > >>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>> On Wed, Dec 5, 2018 at 12:20 PM Jark Wu <
> > [hidden email]>
> > > >>>>>>> wrote:
> > > >>>>>>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> It seems that you have reviewed the DDL doc [1] that
> Lin
> > > >>> and I
> > > >>>>>>>>>>>>> drafted.
> > > >>>>>>>>>>>>>>>> This doc covers all the features running in Alibaba.
> > > >>>>>>>>>>>>>>>> But some of features might be not needed in the first
> > > >>> version
> > > >>>>>> of
> > > >>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>> SQL
> > > >>>>>>>>>>>>>>>> DDL.
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> So my suggestion would be to focus on the MVP DDLs and
> > > >> reach
> > > >>>>>>>>>>>>> agreement
> > > >>>>>>>>>>>>>>> ASAP
> > > >>>>>>>>>>>>>>>> based on the DDL draft [1] and the DDL design [2]
> Shuyi
> > > >>>>>>> proposed.
> > > >>>>>>>>>>>>>>>> And we can discuss on the main differences one by one.
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> The following is the MVP DDLs should be included in
> the
> > > >>> first
> > > >>>>>>>>>> version
> > > >>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>> my
> > > >>>>>>>>>>>>>>>> opinion (feedbacks are welcome):
> > > >>>>>>>>>>>>>>>> (1) Table DDL:
> > > >>>>>>>>>>>>>>>>         (1.1) Type definition
> > > >>>>>>>>>>>>>>>>         (1.2) computed column definition
> > > >>>>>>>>>>>>>>>>         (1.3) watermark definition
> > > >>>>>>>>>>>>>>>>         (1.4) with properties
> > > >>>>>>>>>>>>>>>>         (1.5) table constraint (primary key/unique)
> > > >>>>>>>>>>>>>>>>         (1.6) column nullability (nice to have)
> > > >>>>>>>>>>>>>>>> (2) View DDL
> > > >>>>>>>>>>>>>>>> (3) Function DDL
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> The main differences from two DDL docs (sth maybe
> > missed,
> > > >>>>>>> welcome
> > > >>>>>>>>>> to
> > > >>>>>>>>>>>>>>> point
> > > >>>>>>>>>>>>>>>> out):
> > > >>>>>>>>>>>>>>>> *(1.3) watermark*: this is the main and the most
> > important
> > > >>>>>>>>>>>>> difference,
> > > >>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>> would be great if @Timo Walther <[hidden email]>
> > > >>> @Fabian
> > > >>>>>>>>>> Hueske
> > > >>>>>>>>>>>>>>>> <[hidden email]>  give some feedbacks.
> > > >>>>>>>>>>>>>>>>      (1.1) Type definition:
> > > >>>>>>>>>>>>>>>>           (a) Should VARCHAR carry a length, e.g.
> > > >>> VARCHAR(128)
> > > >>>> ?
> > > >>>>>>>>>>>>>>>>                In most cases, the varchar length is
> not
> > > >> used
> > > >>>>>>> because
> > > >>>>>>>>>>> they
> > > >>>>>>>>>>>>>> are
> > > >>>>>>>>>>>>>>>> stored as String in Flink. But it can be used to
> > optimize
> > > >> in
> > > >>>>>> the
> > > >>>>>>>>>>>>> future
> > > >>>>>>>>>>>>>>> if
> > > >>>>>>>>>>>>>>>> we know the column is a fixed length VARCHAR.
> > > >>>>>>>>>>>>>>>>                So IMO, we can support VARCHAR with
> > length
> > > >> in
> > > >>>> the
> > > >>>>>>>>>> future,
> > > >>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>> just VARCHAR in this version.
> > > >>>>>>>>>>>>>>>>           (b) Should DECIMAL support custom scale and
> > > >>>> precision,
> > > >>>>>>>> e.g.
> > > >>>>>>>>>>>>>>>> DECIMAL(12, 5)?
> > > >>>>>>>>>>>>>>>>                If we clearly know the scale and
> > precision
> > > >> of
> > > >>>> the
> > > >>>>>>>>>>> Decimal,
> > > >>>>>>>>>>>>>> we
> > > >>>>>>>>>>>>>>>> can have some optimization on
> > > >> serialization/deserialization.
> > > >>>>>>> IMO,
> > > >>>>>>>>>> we
> > > >>>>>>>>>>>>>> can
> > > >

[Rong Rong]

Thanks for the summary effort @shuyi. Sorry for jumping in the discussion
so late.

As of the scope of MVP, I think we might want to consider adding "table
update mode" problem to it. I agree with @timo that might not be easily
changed in the future if the flags has to be part of the schema/column
definition.

Regarding the components under discussion.
4) Event-Time Attributes and Watermarks
b, c) I actually like the special indicator way @fabian suggested to hint
Flink to read time attributes directly from the system not the data `(ts AS
SYSTEMROWTIME())`. It should also address the "compute field not emitted"
problem by carrying the "virtual column" concept like @shuyi suggested.
However if I understand correctly, this also required to be defined as part
of the schema/column definition.

3) SOURCE / SINK / BOTH
+1 on not adding properties to `CREATE TABLE` to manage ACL/permission.

On a higher level, I think one question I have is whether we can
definitively come to an agreement that the features under discussion (and
potential solutions) can be cleanly adjusted/added from what we are
providing on MVP (e.g. the schema/column definition might be hard to
achieve but if we all agree ACL/permission should not be part of the
`CREATE TABLE` and a decision can be made later). @shuyi I can also help in
drafting the FLIP doc by summarizing the features under discussion and the
concerns to whether included in the MVP, so that we can carry on the
discussions alongside with the MVP implementation effort. I think each one
of these features deserves a subsection dedicated for it.

Many thanks,
Rong


On Wed, Dec 12, 2018 at 1:14 AM Shuyi Chen <[hidden email]> wrote:

> Hi all,
>
> I summarize the MVP based on the features that we agreed upon. For table
> update mode and custom watermark strategy and ts extractor, I found there
> are some discussions, so I decided to leave them out for the MVP.
> For row/map/array data type, I think we can add it as well if everyone
> agrees.
>
>
> 4) Event-Time Attributes and Watermarks
> Cited from SQL Server 2017 document (
>
> https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2017
> ),
> "A
> computed column is a virtual column that is not physically stored in the
> table, unless the column is marked PERSISTED. A computed column expression
> can use data from other columns to calculate a value for the column to
> which it belongs. " I think we can also use introduce the PERSISTED keyword
> for computed column to indicate that the field can be stored back to the
> table, i.e. ts AS SYSTEMROWTIME() PERSISTED.
>
> 3) SOURCE / SINK / BOTH
> GRANT/INVOKE sounds like a more standard option than adding a property to
> CREATE TABLE to manage the ACL/permission. The ACL can be stored somewhere
> in a database, and allow/disallow access to a dynamic table depending on
> whether it's a "INSERT INTO" or "SELECT".
>
> I can volunteer to put the discussion as a FLIP.  I can try to summarize
> the current discussion, and share edit permission with you to collaborate
> on the documents. After we finalized the doc, we can publish it as a FLIP.
> What do you think?
>
> Shuyi
>
>
>
> On Tue, Dec 11, 2018 at 9:13 AM Timo Walther <[hidden email]> wrote:
>
> > Hi all,
> >
> > thanks for summarizing the discussion @Shuyi. I think we need to include
> > the "table update mode" problem as it might not be changed easily in the
> > future. Regarding "support row/map/array data type", I don't see a
> > problem why we should not support them now as the data types are already
> > included in the runtime. The "support custom timestamp extractor" is
> > solved by the computed columns approach. The "custom watermark strategy"
> > can be added by supplying a class name as paramter in my opinion.
> >
> > Regarding the comments of Lin and Jark:
> >
> > @Lin: Instantiating a TableSource/Sink should not cost much, but we
> > should not mix catalog discussion and DDL at this point.
> >
> > 4) Event-Time Attributes and Watermarks
> > 4.b) Regarding `ts AS SYSTEMROWTIME()` and Lin's comment about "will
> > violate the rule": there is no explicit rule of doing so. Computed
> > column are also not standard compliant, if we can use information that
> > is encoded in constraints we should use it. Adding more and more
> > top-level properties makes the interaction with connectors more
> > difficult. An additional HEADER keyword sounds too connector-specific
> > and also not SQL compliant to me.
> >
> > 3) SOURCE / SINK / BOTH
> > GRANT/INVOKE are mutating an existing table, right? In my opinion,
> > independent of SQL databases but focusing on Flink user requirements, a
> > CREATE TABLE statement should be an immutable definition of a connection
> > to an external system.
> >
> > 7) Table Update Mode
> > As far as I can see, the only thing missing for enabling all table modes
> > is the declaration of a change flag. We could introduce a new keyword
> > here similar to WATERMARK:
> >
> > CREATE TABLE output_kafka_t1(
> >    id bigint,
> >    msg varchar,
> >    CHANGE_FLAG FOR isRetraction
> > ) WITH (
> >    type=kafka
> >    ,...
> > );
> >
> > CREATE TABLE output_kafka_t1(
> >    CHANGE_FLAG FOR isUpsert
> >    id bigint,
> >    msg varchar,
> >    PRIMARY_KEY(id)
> > ) WITH (
> >    type=kafka
> >    ,...
> > );
> >
> > What do you think?
> >
> > @Jark: We should definitely stage the discussions and mention the
> > opinions and advantages/disadvantages that have been proposed already in
> > the FLIP.
> >
> > Regards,
> > Timo
> >
> > Am 10.12.18 um 08:10 schrieb Jark Wu:
> > > Hi all,
> > >
> > > It's great to see we have an agreement on MVP.
> > >
> > > 4.b) Ingesting and writing timestamps to systems.
> > > I would treat the field as a physical column not a virtual column. If
> we
> > > treat it as computed column, it will be confused that the behavior is
> > > different when it is a source or sink.
> > > When it is a physical column, the behavior could be unified. Then the
> > > problem is how to mapping from the field to kafka message timestamp?
> > > One is Lin proposed above and is also used in KSQL[1]. Another idea is
> > > introducing a HEADER column which strictly map by name to the fields in
> > > message header.
> > > For example,
> > >
> > > CREATE TABLE output_kafka_t1(
> > >    id bigint,
> > >    ts timestamp HEADER,
> > >    msg varchar
> > > ) WITH (
> > >    type=kafka
> > >    ,...
> > > );
> > >
> > > This is used in Alibaba but not included in the DDL draft. It will
> > further
> > > extend the SQL syntax, which is we should be cautious about. What do
> you
> > > think about this two solutions?
> > >
> > > 4.d) Custom watermark strategies:
> > > @Timo,  I don't have a strong opinion on this.
> > >
> > > 3) SOURCE/SINK/BOTH
> > > Agree with Lin, GRANT/INVOKE [SELECT|UPDATE] ON TABLE is a clean and
> > > standard way to manage the permission, which is also adopted by HIVE[2]
> > and
> > > many databases.
> > >
> > > [1]:
> https://docs.confluent.io/current/ksql/docs/tutorials/examples.html
> > > [2]:
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=45876173#Hivedeprecatedauthorizationmode/LegacyMode-Grant/RevokePrivileges
> > >
> > > @Timo, it's great if someone can conclude the discussion and summarize
> > into
> > > a FLIP.
> > > @Shuyi, Thanks a lot for putting it all together. The google doc looks
> > good
> > > to me, and I left some minor comments there.
> > >
> > > Regarding to the FLIP, I have some suggestions:
> > > 1. The FLIP can contain MILESTONE1 and FUTURE WORKS.
> > > 2. The MILESTONE1 is the MVP. It describes the MVP DDL syntax.
> > > 3. Separate FUTURE WORKS into two parts: UNDER DISCUSSION and ADOPTED.
> We
> > > can derive MILESTONE2 from this easily when it is ready.
> > >
> > > I summarized the Future Works based on Shuyi's work:
> > >
> > > Adopted: (Should detailed described here...)
> > > 1. support data type nullability and precision.
> > > 2. comment on table and columns.
> > >
> > > Under Discussion: (Should briefly describe some options...)
> > > 1. Ingesting and writing timestamps to systems.
> > > 2. support custom watermark strategy.
> > > 3. support table update mode
> > > 4. support row/map/array data type
> > > 5. support schema derivation
> > > 6. support system versioned temporal table
> > > 7. support table index
> > >
> > > We can continue the further discussion here, also can separate to an
> > other
> > > DISCUSS topic if it is a sophisticated problem such as Table Update
> Mode,
> > > Temporal Table.
> > >
> > > Best,
> > > Jark
> > >
> > > On Mon, 10 Dec 2018 at 11:54, Lin Li <[hidden email]> wrote:
> > >
> > >> hi all,
> > >> Thanks for your valuable input!
> > >>
> > >> 4) Event-Time Attributes and Watermarks:
> > >> 4.b) @Fabian As you mentioned using a computed columns `ts AS
> > >> SYSTEMROWTIME()`
> > >> for writing out to kafka table sink will violate the rule that
> computed
> > >> fields are not emitted.
> > >> Since the timestamp column in kafka's header area is a specific
> > >> materialization protocol,
> > >> why don't we treat it as an connector property? For an example:
> > >> ```
> > >> CREATE TABLE output_kafka_t1(
> > >>    id bigint,
> > >>    ts timestamp,
> > >>    msg varchar
> > >> ) WITH (
> > >>    type=kafka,
> > >>    header.timestamp=ts
> > >>    ,...
> > >> );
> > >> ```
> > >>
> > >> 4d) For custom watermark strategies
> > >> @Fabian Agree with you that opening another topic about this feature
> > later.
> > >>
> > >> 3) SOURCE / SINK / BOTH
> > >> I think the permissions and availabilities are two separately things,
> > >> permissions
> > >> can be managed well by using GRANT/INVOKE(you can call it DCL)
> solutions
> > >> which
> > >> commonly used in different DBs. The permission part can be an new
> topic
> > for
> > >> later discussion, what do you think?
> > >>
> > >> For the availabilities, @Fabian @Timo  I've another question,
> > >> does instantiate a TableSource/Sink cost much or has some other
> > downsides?
> > >> IMO, create a new source/sink object via the construct seems not
> costly.
> > >> When receiving a DDL we should associate it with the catalog object
> > >> (reusing an existence or create a new one).
> > >> Am I lost something important?
> > >>
> > >> 5. Schema declaration:
> > >> @Timo  yes, your concern about the user convenience is very important.
> > But
> > >> I haven't seen a clear way to solve this so far.
> > >> Do we put it later and wait for more inputs from the community?
> > >>
> > >> Shuyi Chen <[hidden email]> 于2018年12月8日周六 下午4:27写道：
> > >>
> > >>> Hi all,
> > >>>
> > >>> Thanks a lot for the great discussion. I think we can continue the
> > >>> discussion here while carving out a MVP so that the community can
> start
> > >>> working on. Based on the discussion so far, I try to summarize what
> we
> > >> will
> > >>> do for the MVP:
> > >>>
> > >>> MVP
> > >>>
> > >>>     1. support CREATE TABLE
> > >>>     2. support exisiting data type in Flink SQL, ignore nullability
> and
> > >>>     precision
> > >>>     3. support table comments and column comments
> > >>>     4. support table constraint PRIMARY KEY and UNIQUE
> > >>>     5. support table properties using key-value pairs
> > >>>     6. support partitioned by
> > >>>     7. support computed column
> > >>>     8. support from-field and from-source timestamp extractors
> > >>>     9. support PERIODIC-ASCENDING, PERIODIC-BOUNDED, FROM-SOURCE
> > watermark
> > >>>     strategies.
> > >>>     10. support a table property to allow explicit enforcement of
> > >>>     read/write(source/sink) permission of a table
> > >>>
> > >>> I try to put up the DDL grammar (
> > >>>
> > >>>
> > >>
> >
> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit?usp=sharing
> > >>> )
> > >>> based on the MVP features above and the previous design docs. Please
> > >> take a
> > >>> look and comment on it.
> > >>>
> > >>>
> > >>> Also, I summarize the future Improvement on CREATE TABLE as the
> > >> followings:
> > >>>     1. support table update mode
> > >>>     2. support data type nullability and precision
> > >>>     3. support row/map/array data type
> > >>>     4. support custom timestamp extractor and watermark strategy
> > >>>     5. support schema derivation
> > >>>     6. support system versioned temporal table
> > >>>     7. support table index
> > >>>
> > >>> I suggest we first agree on the MVP feature list and the MVP grammar.
> > And
> > >>> then we can either continue the discussion of the future improvements
> > >> here,
> > >>> or create separate JIRAs for each item and discuss further in the
> JIRA.
> > >>> What do you guys think?
> > >>>
> > >>> Shuyi
> > >>>
> > >>> On Fri, Dec 7, 2018 at 7:54 AM Timo Walther <[hidden email]>
> > wrote:
> > >>>
> > >>>> Hi all,
> > >>>>
> > >>>> I think we are making good progress. Thanks for all the feedback so
> > >> far.
> > >>>> 3. Sources/Sinks:
> > >>>> It seems that I can not find supporters for explicit SOURCE/SINK
> > >>>> declaration so I'm fine with not using those keywords.
> > >>>> @Fabian: Maybe we don't haven have to change the TableFactory
> > interface
> > >>>> but just provide some helper functions in the TableFactoryService.
> > This
> > >>>> would solve the availability problem, but the permission problem
> would
> > >>>> still not be solved. If you are fine with it, we could introduce a
> > >>>> property instead?
> > >>>>
> > >>>> 5. Schema declaration:
> > >>>> @Lin: We should find an agreement on this as it requires changes to
> > the
> > >>>> TableFactory interface. We should minimize changes to this interface
> > >>>> because it is user-facing. Especially, if format schema and table
> > >> schema
> > >>>> differ, the need for such a functionality is very important. Our
> goal
> > >> is
> > >>>> to connect to existing infrastructure. For example, if we are using
> > >> Avro
> > >>>> and the existing Avro format has enums but Flink SQL does not
> support
> > >>>> enums, it would be helpful to let the Avro format derive a table
> > >> schema.
> > >>>> Otherwise your need to declare both schemas which leads to CREATE
> > TABLE
> > >>>> statements of 400 lines+.
> > >>>> I think the mentioned query:
> > >>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > >>>> format.schema-file = "/my/avrofile.avsc")
> > >>>> is fine and should only be valid if the schema contains no
> > non-computed
> > >>>> columns.
> > >>>>
> > >>>> 7. Table Update Mode:
> > >>>> After thinking about it again, I agree. The mode of the sinks can be
> > >>>> derived from the query and the existence of a PRIMARY KEY
> declaration.
> > >>>> But Fabian raised a very good point. How do we deal with sources?
> > Shall
> > >>>> we introduce a new keywords similar to WATERMARKS such that a
> > >>>> upsert/retract flag is not part of the visible schema?
> > >>>>
> > >>>> 4a. How to mark a field as attribute?
> > >>>> @Jark: Thanks for the explanation of the WATERMARK clause semantics.
> > >>>> This is a nice way of marking existing fields. This sounds good to
> me.
> > >>>>
> > >>>> 4c) WATERMARK as constraint
> > >>>> I'm fine with leaving the WATERMARK clause in the schema definition.
> > >>>>
> > >>>> 4d) Custom watermark strategies:
> > >>>> I would already think about custom watermark strategies as the
> current
> > >>>> descriptor design already supports this. ScalarFunction's don't work
> > as
> > >>>> a PeriodicWatermarkAssigner has different semantics. Why not simply
> > >>>> entering the a full class name here as it is done in the current
> > >> design?
> > >>>> 4.b) Ingesting and writing timestamps to systems (like Kafka)
> > >>>> @Fabian: Yes, your suggestion sounds good to me. This behavior would
> > be
> > >>>> similar to our current `timestamps: from-source` design.
> > >>>>
> > >>>> Once our discussion has found a conclusion, I would like to
> volunteer
> > >>>> and summarize the outcome of this mailing thread. It nicely aligns
> > with
> > >>>> the update work on the connector improvements document (that I
> wanted
> > >> to
> > >>>> do anyway) and the ongoing external catalog discussion.
> Furthermore, I
> > >>>> would also want to propose how to change existing interfaces by
> > keeping
> > >>>> the DDL, connector improvements, and external catalog support in
> mind.
> > >>>> Would that be ok for you?
> > >>>>
> > >>>> Thanks,
> > >>>> Timo
> > >>>>
> > >>>>
> > >>>>
> > >>>> Am 07.12.18 um 14:48 schrieb Fabian Hueske:
> > >>>>> Hi all,
> > >>>>>
> > >>>>> Thanks for the discussion.
> > >>>>> I'd like to share my point of view as well.
> > >>>>>
> > >>>>> 4) Event-Time Attributes and Watermarks:
> > >>>>> 4.a) I agree with Lin and Jark's proposal. Declaring a watermark on
> > >> an
> > >>>>> attribute declares it as an event-time attribute.
> > >>>>> 4.b) Ingesting and writing timestamps to systems (like Kafka). We
> > >> could
> > >>>> use
> > >>>>> a special function like (ts AS SYSTEMROWTIME()). This function will
> > >>>>> indicate that we read the timestamp directly from the system (and
> not
> > >>> the
> > >>>>> data). We can also write the field back to the system when emitting
> > >> the
> > >>>>> table (violating the rule that computed fields are not emitted).
> > >>>>> 4c) I would treat WATERMARK similar to a PRIMARY KEY or UNIQUE KEY
> > >>>>> constraint and therefore keep it in the schema definition.
> > >>>>> 4d) For custom watermark strategies, a simple expressions or
> > >>>>> ScalarFunctions won't be sufficient. Sophisticated approaches could
> > >>>> collect
> > >>>>> histograms, etc. But I think we can leave that out for later.
> > >>>>>
> > >>>>> 3) SOURCE / SINK / BOTH
> > >>>>> As you said, there are two things to consider here: permission and
> > >>>>> availability of a TableSource/TableSink.
> > >>>>> I think that neither should be a reason to add a keyword at such a
> > >>>>> sensitive position.
> > >>>>> However, I also see Timo's point that it would be good to know
> > >> up-front
> > >>>> how
> > >>>>> a table can be used without trying to instantiate a
> TableSource/Sink
> > >>> for
> > >>>> a
> > >>>>> query.
> > >>>>> Maybe we can extend the TableFactory such that it provides
> > >> information
> > >>>>> about which sources/sinks it can provide.
> > >>>>>
> > >>>>> 7. Table Update Mode
> > >>>>> Something that we definitely need to consider is how tables are
> > >>> ingested,
> > >>>>> i.e., append, retract or upsert.
> > >>>>> Especially, since upsert and retraction need a meta-data column
> that
> > >>>>> indicates whether an event is an insert (or upsert) or a delete
> > >> change.
> > >>>>> This column needs to be identified somehow, most likely as part of
> > >> the
> > >>>>> input format. Ideally, this column should not be part of the table
> > >>> schema
> > >>>>> (as it would be always true).
> > >>>>> Emitting tables is not so much of an issue as the properties of the
> > >>> table
> > >>>>> tell use what to do (append-only/update, unique key y/n).
> > >>>>>
> > >>>>> Best,
> > >>>>> Fabian
> > >>>>>
> > >>>>>
> > >>>>> Am Fr., 7. Dez. 2018 um 10:39 Uhr schrieb Jark Wu <
> [hidden email]
> > >>> :
> > >>>>>> Hi Timo,
> > >>>>>>
> > >>>>>> Thanks for your quickly feedback! Here are some of my thoughts:
> > >>>>>>
> > >>>>>> Append, upserts, retract mode on sinks is also a very complex
> > >>> problem. I
> > >>>>>> think append/upserts/retract is the ability of a table, user do
> not
> > >>>> need to
> > >>>>>> specify a table is used for append or retraction or upsert. The
> > >> query
> > >>>> can
> > >>>>>> choose which mode the sink is. If an unbounded groupby is inserted
> > >>> into
> > >>>> an
> > >>>>>> append sink (the sink only implements/supports append), an
> exception
> > >>>> can be
> > >>>>>> thrown. A more complex problem is, if we want to write
> > >>>> retractions/upserts
> > >>>>>> to Kafka, how to encode the change flag (add or retract/delete) on
> > >> the
> > >>>>>> table? Maybe we should propose some protocal for the change flag
> > >>>> encoding,
> > >>>>>> but I don't have a clear idea about this right now.
> > >>>>>>
> > >>>>>> 3. Sources/Sinks: The source/sink tag is similar to the
> > >>>>>> append/upsert/retract problem. Besides source/sink, actully we
> have
> > >>>> stream
> > >>>>>> source, stream sink, batch source, batch sink, and the stream sink
> > >>> also
> > >>>>>> include append/upsert/retract three modes. Should we put all the
> > >> tags
> > >>> on
> > >>>>>> the CREATE TABLE? IMO, the table's ability is defined by the table
> > >>>> itself,
> > >>>>>> user do not need to specify it. If it is only a readable table, an
> > >>>>>> exception can be thrown when write to it. As the source/sink tag
> can
> > >>> be
> > >>>>>> omitted in CREATE TABLE, could we skip it and only support CREATE
> > >>> TABLE
> > >>>> in
> > >>>>>> the first version, and add it back in the future when we really
> need
> > >>>> it? It
> > >>>>>> keeps API compatible and make sure the MVP is what we consider
> > >>> clearly.
> > >>>>>> 4a. How to mark a field as attribute?
> > >>>>>> The watermark definition includes two parts: use which field as
> time
> > >>>>>> attribute and use what generate strategy.
> > >>>>>> When we want to mark `ts` field as attribute: WATERMARK FOR `ts`
> AS
> > >>>> OFFSET
> > >>>>>> '5' SECOND.
> > >>>>>> If we have a POJO{id, user, ts} field named "pojo", we can mark it
> > >>> like
> > >>>>>> this: WATERMARK FOR pojo.ts AS OFFSET '5' SECOND
> > >>>>>>
> > >>>>>> 4b. timestamp write to Kafka message header
> > >>>>>> Even though we can define multiple time attribute on a table, only
> > >> one
> > >>>> time
> > >>>>>> attribute can be actived/used in a query (in a stream). When we
> > >> enable
> > >>>>>> `writeTiemstamp`, the only attribute actived in the stream will be
> > >>>> write to
> > >>>>>> Kafka message header. What I mean the timestmap in StreamRecord is
> > >> the
> > >>>> time
> > >>>>>> attribute in the stream.
> > >>>>>>
> > >>>>>> 4c. Yes. We introduced the WATERMARK keyword similar to the INDEX,
> > >>>> PRIMARY
> > >>>>>> KEY keywords.
> > >>>>>>
> > >>>>>> @Timo, Do you have any other advice or questions on the watermark
> > >>>> syntax ?
> > >>>>>> For example, the builtin strategy name: "BOUNDED WITH OFFSET" VS
> > >>>> "OFFSET"
> > >>>>>> VS ...
> > >>>>>>
> > >>>>>>
> > >>>>>> Cheers,
> > >>>>>> Jark
> > >>>>>>
> > >>>>>> On Fri, 7 Dec 2018 at 17:13, Lin Li <[hidden email]>
> wrote:
> > >>>>>>
> > >>>>>>> Hi Timo,
> > >>>>>>> Thanks for your feedback, here's some thoughts of mine:
> > >>>>>>>
> > >>>>>>> 3. Sources/Sinks:
> > >>>>>>> "Let's assume an interactive CLI session, people should be able
> to
> > >>> list
> > >>>>>> all
> > >>>>>>> source table and sink tables to know upfront if they can use an
> > >>> INSERT
> > >>>>>> INTO
> > >>>>>>> here or not."
> > >>>>>>> This requirement can be simply resolved by a document that list
> all
> > >>>>>>> supported source/sink/both connectors and the sql-client can
> > >> perform
> > >>> a
> > >>>>>>> quick check. It's only an implementation choice, not necessary
> for
> > >>> the
> > >>>>>>> syntax.
> > >>>>>>> For connector implementation, a connector may implement one or
> some
> > >>> or
> > >>>>>> all
> > >>>>>>> of the [Stream|Batch]Source/[Stream|Batch]Sink traits, we can
> > >> derive
> > >>>> the
> > >>>>>>> availability for any give query without the SOURCE/SINk keywords
> or
> > >>>>>>> specific table properties in WITH clause.
> > >>>>>>> Since there's still indeterminacy, shall we skip these two
> keywords
> > >>> for
> > >>>>>> the
> > >>>>>>> MVP DDL? We can make further discussion after users' feedback.
> > >>>>>>>
> > >>>>>>> 6. Partitioning and keys
> > >>>>>>> Agree with you that raise the priority of table constraint and
> > >>>>>> partitioned
> > >>>>>>> table support for better connectivity to Hive and Kafka. I'll add
> > >>>>>>> partitioned table syntax(compatible to hive) into the DDL Draft
> doc
> > >>>>>>> later[1].
> > >>>>>>>
> > >>>>>>> 5. Schema declaration
> > >>>>>>> "if users want to declare computed columns they have a "schema"
> > >>>>>> constraints
> > >>>>>>> but without columns
> > >>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > >>>>>>> format.schema-file = "/my/avrofile.avsc") "
> > >>>>>>>
> > >>>>>>>   From the point of my view, this ddl is invalid because the
> > primary
> > >>> key
> > >>>>>>> constraint already references two columns but types unseen.
> > >>>>>>> And Xuefu pointed a important matching problem, so let's put
> schema
> > >>>>>>> derivation as a follow-up extension ?
> > >>>>>>>
> > >>>>>>>
> > >>>>>>>
> > >>>>>>>
> > >>>>>>> Timo Walther <[hidden email]> 于2018年12月6日周四 下午6:05写道：
> > >>>>>>>
> > >>>>>>>> Hi everyone,
> > >>>>>>>>
> > >>>>>>>> great to have such a lively discussion. My next batch of
> feedback:
> > >>>>>>>>
> > >>>>>>>> @Jark: We don't need to align the descriptor approach with SQL.
> > >> I'm
> > >>>>>> open
> > >>>>>>>> for different approaches as long as we can serve a broad set of
> > >> use
> > >>>>>>>> cases and systems. The descriptor approach was a first attempt
> to
> > >>>> cover
> > >>>>>>>> all aspects and connector/format characteristics. Just another
> > >>>> example,
> > >>>>>>>> that is missing in the DDL design: How can a user decide if
> > >> append,
> > >>>>>>>> retraction, or upserts should be used to sink data into the
> target
> > >>>>>>>> system? Do we want to define all these improtant properties in
> the
> > >>> big
> > >>>>>>>> WITH property map? If yes, we are already close to the
> descriptor
> > >>>>>>>> approach. Regarding the "standard way", most DDL languages have
> > >> very
> > >>>>>>>> custom syntax so there is not a real "standard".
> > >>>>>>>>
> > >>>>>>>> 3. Sources/Sinks: @Lin: If a table has both read/write access it
> > >> can
> > >>>> be
> > >>>>>>>> created using a regular CREATE TABLE (omitting a specific
> > >>> source/sink)
> > >>>>>>>> declaration. Regarding the transition from source/sink to both,
> > >> yes
> > >>> we
> > >>>>>>>> would need to update the a DDL and catalogs. But is this a
> > >> problem?
> > >>>> One
> > >>>>>>>> also needs to add new queries that use the tables. @Xuefu: It is
> > >> not
> > >>>>>>>> only about security aspects. Especially for streaming use cases,
> > >> not
> > >>>>>>>> every connector can be used as a source easily. For example, a
> > >> JDBC
> > >>>>>> sink
> > >>>>>>>> is easier than a JDBC source. Let's assume an interactive CLI
> > >>> session,
> > >>>>>>>> people should be able to list all source table and sink tables
> to
> > >>> know
> > >>>>>>>> upfront if they can use an INSERT INTO here or not.
> > >>>>>>>>
> > >>>>>>>> 6. Partitioning and keys: @Lin: I would like to include this in
> > >> the
> > >>>>>>>> design given that Hive integration and Kafka key support are in
> > >> the
> > >>>>>>>> making/are on our roadmap for this release.
> > >>>>>>>>
> > >>>>>>>> 5. Schema declaration: @Lin: You are right it is not
> conflicting.
> > >> I
> > >>>>>> just
> > >>>>>>>> wanted to raise the point because if users want to declare
> > >> computed
> > >>>>>>>> columns they have a "schema" constraints but without columns.
> Are
> > >> we
> > >>>> ok
> > >>>>>>>> with a syntax like ...
> > >>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > >>>>>>>> format.schema-file = "/my/avrofile.avsc") ?
> > >>>>>>>> @Xuefu: Yes, you are right that an external schema might not
> > >> excatly
> > >>>>>>>> match but this is true for both directions:
> > >>>>>>>> table schema "derives" format schema and format schema "derives"
> > >>> table
> > >>>>>>>> schema.
> > >>>>>>>>
> > >>>>>>>> 7. Hive compatibility: @Xuefu: I agree that Hive is popular but
> we
> > >>>>>>>> should not just adopt everything from Hive as there syntax is
> very
> > >>>>>>>> batch-specific. We should come up with a superset of historical
> > >> and
> > >>>>>>>> future requirements. Supporting Hive queries can be an
> > >> intermediate
> > >>>>>>>> layer on top of Flink's DDL.
> > >>>>>>>>
> > >>>>>>>> 4. Time attributes: @Lin: I'm fine with changing the
> > >>>> TimestampExtractor
> > >>>>>>>> interface as this is also important for better separation of
> > >>> connector
> > >>>>>>>> and table module [1]. However, I'm wondering about watermark
> > >>>>>> generation.
> > >>>>>>>> 4a. timestamps are in the schema twice:
> > >>>>>>>> @Jark: "existing field is Long/Timestamp, we can just use it as
> > >>>>>>>> rowtime": yes, but we need to mark a field as such an attribute.
> > >> How
> > >>>>>>>> does the syntax for marking look like? Also in case of
> timestamps
> > >>> that
> > >>>>>>>> are nested in the schema?
> > >>>>>>>>
> > >>>>>>>> 4b. how can we write out a timestamp into the message header?:
> > >>>>>>>> I agree to simply ignore computed columns when writing out. This
> > >> is
> > >>>>>> like
> > >>>>>>>> 'field-change: add' that I mentioned in the improvements
> document.
> > >>>>>>>> @Jark: "then the timestmap in StreamRecord will be write to
> Kafka
> > >>>>>>>> message header": Unfortunately, there is no timestamp in the
> > >> stream
> > >>>>>>>> record. Additionally, multiple time attributes can be in a
> schema.
> > >>> So
> > >>>>>> we
> > >>>>>>>> need a constraint that tells the sink which column to use
> > >> (possibly
> > >>>>>>>> computed as well)?
> > >>>>>>>>
> > >>>>>>>> 4c. separate all time attribute concerns into a special clause
> > >> next
> > >>> to
> > >>>>>>>> the regular schema?
> > >>>>>>>> @Jark: I don't have a strong opinion on this. I just have the
> > >>> feeling
> > >>>>>>>> that the "schema part" becomes quite messy because the actual
> > >> schema
> > >>>>>>>> with types and fields is accompanied by so much metadata about
> > >>>>>>>> timestamps, watermarks, keys,... and we would need to introduce
> a
> > >>> new
> > >>>>>>>> WATERMARK keyword within a schema that was close to standard up
> to
> > >>>> this
> > >>>>>>>> point.
> > >>>>>>>>
> > >>>>>>>> Thanks everyone,
> > >>>>>>>> Timo
> > >>>>>>>>
> > >>>>>>>> [1] https://issues.apache.org/jira/browse/FLINK-9461
> > >>>>>>>>
> > >>>>>>>>
> > >>>>>>>>
> > >>>>>>>> Am 06.12.18 um 07:08 schrieb Jark Wu:
> > >>>>>>>>> Hi Timo,
> > >>>>>>>>>
> > >>>>>>>>> Thank you for the valuable feedbacks.
> > >>>>>>>>>
> > >>>>>>>>> First of all, I think we don't need to align the SQL
> > >> functionality
> > >>> to
> > >>>>>>>>> Descriptor. Because SQL is a more standard API, we should be as
> > >>>>>>> cautious
> > >>>>>>>> as
> > >>>>>>>>> possible to extend the SQL syntax. If something can be done in
> a
> > >>>>>>> standard
> > >>>>>>>>> way, we shouldn't introduce something new.
> > >>>>>>>>>
> > >>>>>>>>> Here are some of my thoughts:
> > >>>>>>>>>
> > >>>>>>>>> 1. Scope: Agree.
> > >>>>>>>>> 2. Constraints: Agree.
> > >>>>>>>>> 4. Time attributes:
> > >>>>>>>>>      4a. timestamps are in the schema twice.
> > >>>>>>>>>       If an existing field is Long/Timestamp, we can just use
> it
> > >> as
> > >>>>>>>> rowtime,
> > >>>>>>>>> no twice defined. If it is not a Long/Timestamp, we use
> computed
> > >>>>>> column
> > >>>>>>>> to
> > >>>>>>>>> get an expected timestamp column to be rowtime, is this what
> you
> > >>> mean
> > >>>>>>>>> defined twice?  But I don't think it is a problem, but an
> > >>> advantages,
> > >>>>>>>>> because it is easy to use, user do not need to consider whether
> > >> to
> > >>>>>>>> "replace
> > >>>>>>>>> the existing column" or "add a new column", he will not be
> > >> confused
> > >>>>>>>> what's
> > >>>>>>>>> the real schema is, what's the index of rowtime in the schema?
> > >>>>>>> Regarding
> > >>>>>>>> to
> > >>>>>>>>> the optimization, even if timestamps are in schema twice, when
> > >> the
> > >>>>>>>> original
> > >>>>>>>>> timestamp is never used in query, then the projection pushdown
> > >>>>>>>> optimization
> > >>>>>>>>> can cut this field as early as possible, which is exactly the
> > >> same
> > >>> as
> > >>>>>>>>> "replacing the existing column" in runtime.
> > >>>>>>>>>
> > >>>>>>>>>       4b. how can we write out a timestamp into the message
> > >> header?
> > >>>>>>>>>        That's a good point. I think computed column is just a
> > >>> virtual
> > >>>>>>>> column
> > >>>>>>>>> on table which is only relative to reading. If we want to write
> > >> to
> > >>> a
> > >>>>>>>> table
> > >>>>>>>>> with computed column defined, we only need to provide the
> columns
> > >>>>>>> except
> > >>>>>>>>> computed columns (see SQL Server [1]). The computed column is
> > >>> ignored
> > >>>>>>> in
> > >>>>>>>>> the insert statement. Get back to the question, how can we
> write
> > >>> out
> > >>>>>> a
> > >>>>>>>>> timestamp into the message header? IMO, we can provide a
> > >>>>>> configuration
> > >>>>>>> to
> > >>>>>>>>> support this, such as `kafka.writeTimestamp=true`, then the
> > >>> timestmap
> > >>>>>>> in
> > >>>>>>>>> StreamRecord will be write to Kafka message header. What do you
> > >>>>>> think?
> > >>>>>>>>>        4c. separate all time attribute concerns into a special
> > >>> clause
> > >>>>>>> next
> > >>>>>>>> to
> > >>>>>>>>> the regular schema?
> > >>>>>>>>>        Separating watermark into a special clause similar to
> > >>>>>> PARTITIONED
> > >>>>>>>> BY is
> > >>>>>>>>> also a good idea. Conceptually, it's fine to put watermark in
> > >>> schema
> > >>>>>>> part
> > >>>>>>>>> or out schema part. But if we want to support multiple
> watermark
> > >>>>>>>>> definition, maybe it would be better to put it in schema part.
> It
> > >>> is
> > >>>>>>>>> similar to Index Definition that we can define several indexes
> > >> on a
> > >>>>>>> table
> > >>>>>>>>> in schema part.
> > >>>>>>>>>
> > >>>>>>>>>        4d. How can people come up with a custom watermark
> > >> strategy?
> > >>>>>>>>>        In most cases, the built-in strategy can works good. If
> we
> > >>> need
> > >>>>>> a
> > >>>>>>>>> custom one, we can use a scalar function which restrict to only
> > >>>>>> return
> > >>>>>>> a
> > >>>>>>>>> nullable Long, and use it in SQL like: WATERMARK for rowtime AS
> > >>>>>>>>> watermarkUdf(a, b, c). The `watermarkUdf` is a user-defined
> > >> scalar
> > >>>>>>>> function
> > >>>>>>>>> accepts 3 parameters and return a nullable Long which can be
> used
> > >>> as
> > >>>>>>>>> punctuated watermark assigner. Another choice is implementing a
> > >>> class
> > >>>>>>>>> extending the
> > >>>>>>>>> `org.apache.flink.table.sources.wmstrategies.WatermarkStrategy`
> > >> and
> > >>>>>> use
> > >>>>>>>> it
> > >>>>>>>>> in SQL: WATERMARK for rowtime AS 'com.my.MyWatermarkStrategy'.
> > >> But
> > >>> if
> > >>>>>>>>> scalar function can cover the requirements here, I would prefer
> > >> it
> > >>>>>>> here,
> > >>>>>>>>> because it keeps standard compliant. BTW, this feature is not
> in
> > >>> MVP,
> > >>>>>>> we
> > >>>>>>>>> can discuss it more depth in the future when we need it.
> > >>>>>>>>>
> > >>>>>>>>> 5. Schema declaration:
> > >>>>>>>>> I like the proposal to omit the schema if we can get the schema
> > >>> from
> > >>>>>>>>> external storage or something schema file. Actually, we have
> > >>> already
> > >>>>>>>>> encountered this requirement in out company.
> > >>>>>>>>>
> > >>>>>>>>>
> > >>>>>>>>> +1 to @Xuefu that we should be as close as possible to Hive
> > >> syntax
> > >>>>>>> while
> > >>>>>>>>> keeping SQL ANSI standard. This will make it more acceptable
> and
> > >>>>>> reduce
> > >>>>>>>> the
> > >>>>>>>>> learning cost for user.
> > >>>>>>>>>
> > >>>>>>>>> [1]:
> > >>>>>>>>>
> > >>
> >
> https://docs.microsoft.com/en-us/sql/relational-databases/partitions/create-partitioned-tables-and-indexes?view=sql-server-2017
> > >>>>>>>>> Best,
> > >>>>>>>>> Jark
> > >>>>>>>>>
> > >>>>>>>>> On Thu, 6 Dec 2018 at 12:09, Zhang, Xuefu <
> > >> [hidden email]
> > >>>>>>>> wrote:
> > >>>>>>>>>> Hi Timo/Shuyi/Lin,
> > >>>>>>>>>>
> > >>>>>>>>>> Thanks for the discussions. It seems that we are converging to
> > >>>>>>> something
> > >>>>>>>>>> meaningful. Here are some of my thoughts:
> > >>>>>>>>>>
> > >>>>>>>>>> 1. +1 on MVP DDL
> > >>>>>>>>>> 3. Markers for source or sink seem more about permissions on
> > >>> tables
> > >>>>>>> that
> > >>>>>>>>>> belong to a security component. Unless the table is created
> > >>>>>>> differently
> > >>>>>>>>>> based on source, sink, or both, it doesn't seem necessary to
> use
> > >>>>>> these
> > >>>>>>>>>> keywords to enforce permissions.
> > >>>>>>>>>> 5. It might be okay if schema declaration is always needed.
> > >> While
> > >>>>>>> there
> > >>>>>>>>>> might be some duplication sometimes, it's not always true. For
> > >>>>>>> example,
> > >>>>>>>>>> external schema may not be exactly matching Flink schema. For
> > >>>>>>> instance,
> > >>>>>>>>>> data types. Even if so, perfect match is not required. For
> > >>> instance,
> > >>>>>>> the
> > >>>>>>>>>> external schema file may evolve while table schema in Flink
> may
> > >>> stay
> > >>>>>>>>>> unchanged. A responsible reader should be able to scan the
> file
> > >>>>>> based
> > >>>>>>> on
> > >>>>>>>>>> file schema and return the data based on table schema.
> > >>>>>>>>>>
> > >>>>>>>>>> Other aspects:
> > >>>>>>>>>>
> > >>>>>>>>>> 7. Hive compatibility. Since Flink SQL will soon be able to
> > >>> operate
> > >>>>>> on
> > >>>>>>>>>> Hive metadata and data, it's an add-on benefit if we can be
> > >>>>>> compatible
> > >>>>>>>> with
> > >>>>>>>>>> Hive syntax/semantics while following ANSI standard. At least
> we
> > >>>>>>> should
> > >>>>>>>> be
> > >>>>>>>>>> as close as possible. Hive DDL can found at
> > >>>>>>>>>>
> > >>> https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL
> > >>>>>>>>>> Thanks,
> > >>>>>>>>>> Xuefu
> > >>>>>>>>>>
> > >>>>>>>>>>
> > >>>>>>>>>>
> > >>>>>>>>>>
> > >> ------------------------------------------------------------------
> > >>>>>>>>>> Sender:Lin Li <[hidden email]>
> > >>>>>>>>>> Sent at:2018 Dec 6 (Thu) 10:49
> > >>>>>>>>>> Recipient:dev <[hidden email]>
> > >>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> > >>>>>>>>>>
> > >>>>>>>>>> Hi Timo and Shuyi,
> > >>>>>>>>>>      thanks for your feedback.
> > >>>>>>>>>>
> > >>>>>>>>>> 1. Scope
> > >>>>>>>>>> agree with you we should focus on the MVP DDL first.
> > >>>>>>>>>>
> > >>>>>>>>>> 2. Constraints
> > >>>>>>>>>> yes, this can be a follow-up issue.
> > >>>>>>>>>>
> > >>>>>>>>>> 3. Sources/Sinks
> > >>>>>>>>>> If a TABLE has both read/write access requirements, should we
> > >>>>>> declare
> > >>>>>>> it
> > >>>>>>>>>> using
> > >>>>>>>>>> `CREATE [SOURCE_SINK|BOTH] TABLE tableName ...` ? A further
> > >>>>>> question,
> > >>>>>>>> if a
> > >>>>>>>>>> TABLE
> > >>>>>>>>>> t1 firstly declared as read only (as a source table), then for
> > >>> some
> > >>>>>>> new
> > >>>>>>>>>> requirements
> > >>>>>>>>>> t1 will change to a sink table,  in this case we need updating
> > >>> both
> > >>>>>>> the
> > >>>>>>>> DDL
> > >>>>>>>>>> and catalogs.
> > >>>>>>>>>> Further more, let's think about the BATCH query, update one
> > >> table
> > >>>>>>>> in-place
> > >>>>>>>>>> can be a common case.
> > >>>>>>>>>> e.g.,
> > >>>>>>>>>> ```
> > >>>>>>>>>> CREATE TABLE t1 (
> > >>>>>>>>>>      col1 varchar,
> > >>>>>>>>>>      col2 int,
> > >>>>>>>>>>      col3 varchar
> > >>>>>>>>>>      ...
> > >>>>>>>>>> );
> > >>>>>>>>>>
> > >>>>>>>>>> INSERT [OVERWRITE] TABLE t1
> > >>>>>>>>>> AS
> > >>>>>>>>>> SELECT
> > >>>>>>>>>>      (some computing ...)
> > >>>>>>>>>> FROM t1;
> > >>>>>>>>>> ```
> > >>>>>>>>>> So, let's forget these SOURCE/SINK keywords in DDL. For the
> > >>>>>> validation
> > >>>>>>>>>> purpose, we can find out other ways.
> > >>>>>>>>>>
> > >>>>>>>>>> 4. Time attributes
> > >>>>>>>>>> As Shuyi mentioned before, there exists an
> > >>>>>>>>>>
> `org.apache.flink.table.sources.tsextractors.TimestampExtractor`
> > >>> for
> > >>>>>>>> custom
> > >>>>>>>>>> defined time attributes usage, but this expression based class
> > >> is
> > >>>>>> more
> > >>>>>>>>>> friendly for table api not the SQL.
> > >>>>>>>>>> ```
> > >>>>>>>>>> /**
> > >>>>>>>>>>      * Provides the an expression to extract the timestamp
> for a
> > >>>>>> rowtime
> > >>>>>>>>>> attribute.
> > >>>>>>>>>>      */
> > >>>>>>>>>> abstract class TimestampExtractor extends FieldComputer[Long]
> > >> with
> > >>>>>>>>>> Serializable {
> > >>>>>>>>>>
> > >>>>>>>>>>      /** Timestamp extractors compute the timestamp as Long.
> */
> > >>>>>>>>>>      override def getReturnType: TypeInformation[Long] =
> > >>>>>>>>>> Types.LONG.asInstanceOf[TypeInformation[Long]]
> > >>>>>>>>>> }
> > >>>>>>>>>> ```
> > >>>>>>>>>> BTW, I think both the Scalar function and the
> TimestampExtractor
> > >>> are
> > >>>>>>>>>> expressing computing logic, the TimestampExtractor has no more
> > >>>>>>>> advantage in
> > >>>>>>>>>> SQL scenarios.
> > >>>>>>>>>>
> > >>>>>>>>>>
> > >>>>>>>>>> 6. Partitioning and keys
> > >>>>>>>>>> Primary Key is included in Constraint part, and partitioned
> > >> table
> > >>>>>>>> support
> > >>>>>>>>>> can be another topic later.
> > >>>>>>>>>>
> > >>>>>>>>>> 5. Schema declaration
> > >>>>>>>>>> Agree with you that we can do better schema derivation for
> user
> > >>>>>>>>>> convenience, but this is not conflict with the syntax.
> > >>>>>>>>>> Table properties can carry any useful informations both for
> the
> > >>>>>> users
> > >>>>>>>> and
> > >>>>>>>>>> the framework, I like your `contract name` proposal,
> > >>>>>>>>>> e.g., `WITH (format.type = avro)`, the framework can recognize
> > >>> some
> > >>>>>>>>>> `contract name` like `format.type`, `connector.type` and etc.
> > >>>>>>>>>> And also derive the table schema from an existing schema file
> > >> can
> > >>> be
> > >>>>>>>> handy
> > >>>>>>>>>> especially one with too many table columns.
> > >>>>>>>>>>
> > >>>>>>>>>> Regards,
> > >>>>>>>>>> Lin
> > >>>>>>>>>>
> > >>>>>>>>>>
> > >>>>>>>>>> Timo Walther <[hidden email]> 于2018年12月5日周三 下午10:40写道：
> > >>>>>>>>>>
> > >>>>>>>>>>> Hi Jark and Shuyi,
> > >>>>>>>>>>>
> > >>>>>>>>>>> thanks for pushing the DDL efforts forward. I agree that we
> > >>> should
> > >>>>>>> aim
> > >>>>>>>>>>> to combine both Shuyi's design and your design.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Here are a couple of concerns that I think we should address
> in
> > >>> the
> > >>>>>>>>>> design:
> > >>>>>>>>>>> 1. Scope: Let's focuses on a MVP DDL for CREATE TABLE
> > >> statements
> > >>>>>>> first.
> > >>>>>>>>>>> I think this topic has already enough potential for long
> > >>>>>> discussions
> > >>>>>>>> and
> > >>>>>>>>>>> is very helpful for users. We can discuss CREATE VIEW and
> > >> CREATE
> > >>>>>>>>>>> FUNCTION afterwards as they are not related to each other.
> > >>>>>>>>>>>
> > >>>>>>>>>>> 2. Constraints: I think we should consider things like
> > >>> nullability,
> > >>>>>>>>>>> VARCHAR length, and decimal scale and precision in the future
> > >> as
> > >>>>>> they
> > >>>>>>>>>>> allow for nice optimizations. However, since both the
> > >> translation
> > >>>>>> and
> > >>>>>>>>>>> runtime operators do not support those features. I would not
> > >>>>>>> introduce
> > >>>>>>>> a
> > >>>>>>>>>>> arbitrary default value but omit those parameters for now.
> This
> > >>> can
> > >>>>>>> be
> > >>>>>>>> a
> > >>>>>>>>>>> follow-up issue once the basic DDL has been merged.
> > >>>>>>>>>>>
> > >>>>>>>>>>> 3. Sources/Sinks: We had a discussion about CREATE TABLE vs
> > >>> CREATE
> > >>>>>>>>>>> [SOURCE|SINK|] TABLE before. In my opinion we should allow
> for
> > >>>>>> these
> > >>>>>>>>>>> explicit declaration because in most production scenarios,
> > >> teams
> > >>>>>> have
> > >>>>>>>>>>> strict read/write access requirements. For example, a data
> > >>> science
> > >>>>>>> team
> > >>>>>>>>>>> should only consume from a event Kafka topic but should not
> > >>>>>>> accidently
> > >>>>>>>>>>> write back to the single source of truth.
> > >>>>>>>>>>>
> > >>>>>>>>>>> 4. Time attributes: In general, I like your computed columns
> > >>>>>> approach
> > >>>>>>>>>>> because it makes defining a rowtime attributes transparent
> and
> > >>>>>>> simple.
> > >>>>>>>>>>> However, there are downsides that we should discuss.
> > >>>>>>>>>>> 4a. Jarks current design means that timestamps are in the
> > >> schema
> > >>>>>>> twice.
> > >>>>>>>>>>> The design that is mentioned in [1] makes this more flexible
> as
> > >>> it
> > >>>>>>>>>>> either allows to replace an existing column or add a computed
> > >>>>>> column.
> > >>>>>>>>>>> 4b. We need to consider the zoo of storage systems that is
> out
> > >>>>>> there
> > >>>>>>>>>>> right now. Take Kafka as an example, how can we write out a
> > >>>>>> timestamp
> > >>>>>>>>>>> into the message header? We need to think of a reverse
> > >> operation
> > >>>>>> to a
> > >>>>>>>>>>> computed column.
> > >>>>>>>>>>> 4c. Does defining a watermark really fit into the schema part
> > >> of
> > >>> a
> > >>>>>>>>>>> table? Shouldn't we separate all time attribute concerns
> into a
> > >>>>>>> special
> > >>>>>>>>>>> clause next to the regular schema, similar how PARTITIONED BY
> > >>> does
> > >>>>>> it
> > >>>>>>>> in
> > >>>>>>>>>>> Hive?
> > >>>>>>>>>>> 4d. How can people come up with a custom watermark strategy?
> I
> > >>>>>> guess
> > >>>>>>>>>>> this can not be implemented in a scalar function and would
> > >>> require
> > >>>>>>> some
> > >>>>>>>>>>> new type of UDF?
> > >>>>>>>>>>>
> > >>>>>>>>>>> 6. Partitioning and keys: Another question that the DDL
> design
> > >>>>>> should
> > >>>>>>>>>>> answer is how do we express primary keys (for upserts),
> > >>>>>> partitioning
> > >>>>>>>>>>> keys (for Hive, Kafka message keys). All part of the table
> > >>> schema?
> > >>>>>>>>>>> 5. Schema declaration: I find it very annoying that we want
> to
> > >>>>>> force
> > >>>>>>>>>>> people to declare all columns and types again even though
> this
> > >> is
> > >>>>>>>>>>> usually already defined in some company-wide format. I know
> > >> that
> > >>>>>>>> catalog
> > >>>>>>>>>>> support will greatly improve this. But if no catalog is used,
> > >>>>>> people
> > >>>>>>>>>>> need to manually define a schema with 50+ fields in a Flink
> > >> DDL.
> > >>>>>>> What I
> > >>>>>>>>>>> actually promoted having two ways of reading data:
> > >>>>>>>>>>>
> > >>>>>>>>>>> 1. Either the format derives its schema from the table
> schema.
> > >>>>>>>>>>> CREATE TABLE (col INT) WITH (format.type = avro)
> > >>>>>>>>>>>
> > >>>>>>>>>>> 2. Or the table schema can be omitted and the format schema
> > >>> defines
> > >>>>>>> the
> > >>>>>>>>>>> table schema (+ time attributes).
> > >>>>>>>>>>> CREATE TABLE WITH (format.type = avro, format.schema-file =
> > >>>>>>>>>>> "/my/avrofile.avsc")
> > >>>>>>>>>>>
> > >>>>>>>>>>> Please let me know what you think about each item. I will try
> > >> to
> > >>>>>>>>>>> incorporate your feedback in [1] this week.
> > >>>>>>>>>>>
> > >>>>>>>>>>> Regards,
> > >>>>>>>>>>> Timo
> > >>>>>>>>>>>
> > >>>>>>>>>>> [1]
> > >>>>>>>>>>>
> > >>>>>>>>>>>
> > >>
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit#heading=h.41fd6rs7b3cf
> > >>>>>>>>>>> Am 05.12.18 um 13:01 schrieb Jark Wu:
> > >>>>>>>>>>>> Hi Shuyi,
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> It's exciting to see we can make such a great progress here.
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> Regarding to the watermark:
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> Watermarks can be defined on any columns (including
> > >>>>>> computed-column)
> > >>>>>>>> in
> > >>>>>>>>>>>> table schema.
> > >>>>>>>>>>>> The computed column can be computed from existing columns
> > >> using
> > >>>>>>>> builtin
> > >>>>>>>>>>>> functions and *UserDefinedFunctions* (ScalarFunction).
> > >>>>>>>>>>>> So IMO, it can work out for almost all the scenarios not
> only
> > >>>>>> common
> > >>>>>>>>>>>> scenarios.
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> I don't think using a `TimestampExtractor` to support custom
> > >>>>>>> timestamp
> > >>>>>>>>>>>> extractor in SQL is a good idea. Because
> `TimestampExtractor`
> > >>>>>>>>>>>> is not a SQL standard function. If we support
> > >>> `TimestampExtractor`
> > >>>>>>> in
> > >>>>>>>>>>> SQL,
> > >>>>>>>>>>>> do we need to support CREATE FUNCTION for
> > >> `TimestampExtractor`?
> > >>>>>>>>>>>> I think `ScalarFunction` can do the same thing with
> > >>>>>>>>>> `TimestampExtractor`
> > >>>>>>>>>>>> but more powerful and standard.
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> The core idea of the watermark definition syntax is that the
> > >>>>>> schema
> > >>>>>>>>>> part
> > >>>>>>>>>>>> defines all the columns of the table, it is exactly what the
> > >>> query
> > >>>>>>>>>> sees.
> > >>>>>>>>>>>> The watermark part is something like a primary key
> definition
> > >> or
> > >>>>>>>>>>> constraint
> > >>>>>>>>>>>> on SQL Table, it has no side effect on the schema, only
> > >> defines
> > >>>>>> what
> > >>>>>>>>>>>> watermark strategy is and makes which field as the rowtime
> > >>>>>> attribute
> > >>>>>>>>>>> field.
> > >>>>>>>>>>>> If the rowtime field is not in the existing fields, we can
> use
> > >>>>>>>> computed
> > >>>>>>>>>>>> column
> > >>>>>>>>>>>> to generate it from other existing fields. The Descriptor
> > >>> Pattern
> > >>>>>>> API
> > >>>>>>>>>> [1]
> > >>>>>>>>>>>> is very useful when writing a Table API job, but is not
> > >>>>>>> contradictory
> > >>>>>>>>>> to
> > >>>>>>>>>>>> the
> > >>>>>>>>>>>> Watermark DDL from my perspective.
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> [1]:
> > >>>>>>>>>>>>
> > >>
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > >>>>>>>>>>>> .
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> Best,
> > >>>>>>>>>>>> Jark
> > >>>>>>>>>>>>
> > >>>>>>>>>>>> On Wed, 5 Dec 2018 at 17:58, Shuyi Chen <[hidden email]
> >
> > >>>>>> wrote:
> > >>>>>>>>>>>>> Hi Jark and Shaoxuan,
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> Thanks a lot for the summary. I think we are making great
> > >>>>>> progress
> > >>>>>>>>>> here.
> > >>>>>>>>>>>>> Below are my thoughts.
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> *(1) watermark definition
> > >>>>>>>>>>>>> IMO, it's better to keep it consistent with the rowtime
> > >>>>>> extractors
> > >>>>>>>> and
> > >>>>>>>>>>>>> watermark strategies defined in
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>>
> > >>
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > >>>>>>>>>>>>> .
> > >>>>>>>>>>>>> Using built-in functions seems to be too much for most of
> the
> > >>>>>>> common
> > >>>>>>>>>>>>> scenarios.
> > >>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > >>>>>>>>>>>>> Actually, I think we can put the source/sink type info into
> > >> the
> > >>>>>>> table
> > >>>>>>>>>>>>> properties, so we can use CREATE TABLE.
> > >>>>>>>>>>>>> (3) View DDL with properties
> > >>>>>>>>>>>>> We can remove the view properties section now for the MVP
> and
> > >>> add
> > >>>>>>> it
> > >>>>>>>>>>> back
> > >>>>>>>>>>>>> later if needed.
> > >>>>>>>>>>>>> (4) Type Definition
> > >>>>>>>>>>>>> I agree we can put the type length or precision into future
> > >>>>>>> versions.
> > >>>>>>>>>> As
> > >>>>>>>>>>>>> for the grammar difference, currently, I am using the
> grammar
> > >>> in
> > >>>>>>>>>> Calcite
> > >>>>>>>>>>>>> type DDL, but since we'll extend the parser in Flink, so we
> > >> can
> > >>>>>>>>>>> definitely
> > >>>>>>>>>>>>> change if needed.
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> Shuyi
> > >>>>>>>>>>>>>
> > >>>>>>>>>>>>> On Tue, Dec 4, 2018 at 10:48 PM Jark Wu <[hidden email]>
> > >>>>>> wrote:
> > >>>>>>>>>>>>>> Hi Shaoxuan,
> > >>>>>>>>>>>>>>
> > >>>>>>>>>>>>>> Thanks for pointing that out. Yes, the source/sink tag on
> > >>> create
> > >>>>>>>>>> table
> > >>>>>>>>>>> is
> > >>>>>>>>>>>>>> the another major difference.
> > >>>>>>>>>>>>>>
> > >>>>>>>>>>>>>> Summarize the main differences again:
> > >>>>>>>>>>>>>>
> > >>>>>>>>>>>>>> *(1) watermark definition
> > >>>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > >>>>>>>>>>>>>> (3) View DDL with properties
> > >>>>>>>>>>>>>> (4) Type Definition
> > >>>>>>>>>>>>>>
> > >>>>>>>>>>>>>> Best,
> > >>>>>>>>>>>>>> Jark
> > >>>>>>>>>>>>>>
> > >>>>>>>>>>>>>> On Wed, 5 Dec 2018 at 14:08, Shaoxuan Wang <
> > >>> [hidden email]
> > >>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>> Hi Jark,
> > >>>>>>>>>>>>>>> Thanks for the summary. Your plan for the 1st round
> > >>>>>>> implementation
> > >>>>>>>>>> of
> > >>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>> looks good to me.
> > >>>>>>>>>>>>>>> Have we reached the agreement on simplifying/unifying
> > >> "create
> > >>>>>>>>>>>>>> [source/sink]
> > >>>>>>>>>>>>>>> table" to "create table"? "Watermark definition" and
> > >> "create
> > >>>>>>> table"
> > >>>>>>>>>>> are
> > >>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>> major obstacles on the way to merge two design proposals
> > >>> FMPOV.
> > >>>>>>>>>>> @Shuyi,
> > >>>>>>>>>>>>>> It
> > >>>>>>>>>>>>>>> would be great if you can spend time and respond to these
> > >> two
> > >>>>>>> parts
> > >>>>>>>>>>>>>> first.
> > >>>>>>>>>>>>>>> Regards,
> > >>>>>>>>>>>>>>> Shaoxuan
> > >>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>> On Wed, Dec 5, 2018 at 12:20 PM Jark Wu <
> [hidden email]>
> > >>>>>>> wrote:
> > >>>>>>>>>>>>>>>> Hi Shuyi,
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>> It seems that you have reviewed the DDL doc [1] that Lin
> > >>> and I
> > >>>>>>>>>>>>> drafted.
> > >>>>>>>>>>>>>>>> This doc covers all the features running in Alibaba.
> > >>>>>>>>>>>>>>>> But some of features might be not needed in the first
> > >>> version
> > >>>>>> of
> > >>>>>>>>>>>>> Flink
> > >>>>>>>>>>>>>>> SQL
> > >>>>>>>>>>>>>>>> DDL.
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>> So my suggestion would be to focus on the MVP DDLs and
> > >> reach
> > >>>>>>>>>>>>> agreement
> > >>>>>>>>>>>>>>> ASAP
> > >>>>>>>>>>>>>>>> based on the DDL draft [1] and the DDL design [2] Shuyi
> > >>>>>>> proposed.
> > >>>>>>>>>>>>>>>> And we can discuss on the main differences one by one.
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>> The following is the MVP DDLs should be included in the
> > >>> first
> > >>>>>>>>>> version
> > >>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>> my
> > >>>>>>>>>>>>>>>> opinion (feedbacks are welcome):
> > >>>>>>>>>>>>>>>> (1) Table DDL:
> > >>>>>>>>>>>>>>>>         (1.1) Type definition
> > >>>>>>>>>>>>>>>>         (1.2) computed column definition
> > >>>>>>>>>>>>>>>>         (1.3) watermark definition
> > >>>>>>>>>>>>>>>>         (1.4) with properties
> > >>>>>>>>>>>>>>>>         (1.5) table constraint (primary key/unique)
> > >>>>>>>>>>>>>>>>         (1.6) column nullability (nice to have)
> > >>>>>>>>>>>>>>>> (2) View DDL
> > >>>>>>>>>>>>>>>> (3) Function DDL
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>> The main differences from two DDL docs (sth maybe
> missed,
> > >>>>>>> welcome
> > >>>>>>>>>> to
> > >>>>>>>>>>>>>>> point
> > >>>>>>>>>>>>>>>> out):
> > >>>>>>>>>>>>>>>> *(1.3) watermark*: this is the main and the most
> important
> > >>>>>>>>>>>>> difference,
> > >>>>>>>>>>>>>> it
> > >>>>>>>>>>>>>>>> would be great if @Timo Walther <[hidden email]>
> > >>> @Fabian
> > >>>>>>>>>> Hueske
> > >>>>>>>>>>>>>>>> <[hidden email]>  give some feedbacks.
> > >>>>>>>>>>>>>>>>      (1.1) Type definition:
> > >>>>>>>>>>>>>>>>           (a) Should VARCHAR carry a length, e.g.
> > >>> VARCHAR(128)
> > >>>> ?
> > >>>>>>>>>>>>>>>>                In most cases, the varchar length is not
> > >> used
> > >>>>>>> because
> > >>>>>>>>>>> they
> > >>>>>>>>>>>>>> are
> > >>>>>>>>>>>>>>>> stored as String in Flink. But it can be used to
> optimize
> > >> in
> > >>>>>> the
> > >>>>>>>>>>>>> future
> > >>>>>>>>>>>>>>> if
> > >>>>>>>>>>>>>>>> we know the column is a fixed length VARCHAR.
> > >>>>>>>>>>>>>>>>                So IMO, we can support VARCHAR with
> length
> > >> in
> > >>>> the
> > >>>>>>>>>> future,
> > >>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>> just VARCHAR in this version.
> > >>>>>>>>>>>>>>>>           (b) Should DECIMAL support custom scale and
> > >>>> precision,
> > >>>>>>>> e.g.
> > >>>>>>>>>>>>>>>> DECIMAL(12, 5)?
> > >>>>>>>>>>>>>>>>                If we clearly know the scale and
> precision
> > >> of
> > >>>> the
> > >>>>>>>>>>> Decimal,
> > >>>>>>>>>>>>>> we
> > >>>>>>>>>>>>>>>> can have some optimization on
> > >> serialization/deserialization.
> > >>>>>>> IMO,
> > >>>>>>>>>> we
> > >>>>>>>>>>>>>> can
> > >>>>>>>>>>>>>>>> support just support DECIMAL in this version,
> > >>>>>>>>>>>>>>>>                which means DECIMAL(38, 18) as default.
> And
> > >>>>>> support
> > >>>>>>>>>>> custom
> > >>>>>>>>>>>>>>> scale
> > >>>>>>>>>>>>>>>> and precision in the future.
> > >>>>>>>>>>>>>>>>      (2) View DDL: Do we need WITH properties in View
> DDL
> > >>>>>>> (proposed
> > >>>>>>>> in
> > >>>>>>>>>>>>>>> doc[2])?
> > >>>>>>>>>>>>>>>> What are the properties on the view used for?
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>> The features could be supported and discussed in the
> > >> future:
> > >>>>>>>>>>>>>>>> (1) period definition on table
> > >>>>>>>>>>>>>>>> (2) Type DDL
> > >>>>>>>>>>>>>>>> (3) Index DDL
> > >>>>>>>>>>>>>>>> (4) Library DDL
> > >>>>>>>>>>>>>>>> (5) Drop statement
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>> [1] Flink DDL draft by Lin and Jark:
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>
> > >>
> >
> https://docs.google.com/document/d/1o16jC-AxnZoxMfHQptkKQkSC6ZDDBRhKg6gm8VGnY-k/edit#
> > >>>>>>>>>>>>>>>> [2] Flink SQL DDL design by Shuyi:
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>
> > >>
> >
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit#
> > >>>>>>>>>>>>>>>> Cheers,
> > >>>>>>>>>>>>>>>> Jark
> > >>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>> On Thu, 29 Nov 2018 at 16:13, Shaoxuan Wang <
> > >>>>>>> [hidden email]>
> > >>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>> Sure Shuyu,
> > >>>>>>>>>>>>>>>>> What I hope is that we can reach an agreement on DDL
> > >> gramma
> > >>>>>> as
> > >>>>>>>>>> soon
> > >>>>>>>>>>>>>> as
> > >>>>>>>>>>>>>>>>> possible. There are a few differences between your
> > >> proposal
> > >>>>>> and
> > >>>>>>>>>>>>> ours.
> > >>>>>>>>>>>>>>>> Once
> > >>>>>>>>>>>>>>>>> Lin and Jark propose our design, we can quickly discuss
> > >> on
> > >>>>>> the
> > >>>>>>>>>>>>> those
> > >>>>>>>>>>>>>>>>> differences, and see how far away towards a unified
> > >> design.
> > >>>>>>>>>>>>>>>>> WRT the external catalog, I think it is an orthogonal
> > >>> topic,
> > >>>>>> we
> > >>>>>>>>>> can
> > >>>>>>>>>>>>>>>> design
> > >>>>>>>>>>>>>>>>> it in parallel. I believe @Xuefu, @Bowen are already
> > >>> working
> > >>>>>>> on.
> > >>>>>>>>>> We
> > >>>>>>>>>>>>>>>>> should/will definitely involve them to review the final
> > >>>>>> design
> > >>>>>>> of
> > >>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>> implementation. I would suggest that we should give it
> a
> > >>>>>> higher
> > >>>>>>>>>>>>>>> priority
> > >>>>>>>>>>>>>>>> on
> > >>>>>>>>>>>>>>>>> the DDL implementation, as it is a crucial component
> for
> > >>> the
> > >>>>>>> user
> > >>>>>>>>>>>>>>>>> experience of SQL_CLI.
> > >>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>> Regards,
> > >>>>>>>>>>>>>>>>> Shaoxuan
> > >>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>> On Thu, Nov 29, 2018 at 6:56 AM Shuyi Chen <
> > >>>>>> [hidden email]
> > >>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>> Thanks a lot, Shaoxuan, Jack and Lin. We should
> > >> definitely
> > >>>>>>>>>>>>>>> collaborate
> > >>>>>>>>>>>>>>>>>> here, we have also our own DDL implementation running
> in
> > >>>>>>>>>>>>> production
> > >>>>>>>>>>>>>>> for
> > >>>>>>>>>>>>>>>>>> almost 2 years at Uber. With the joint experience from
> > >>> both
> > >>>>>>>>>>>>>>> companies,
> > >>>>>>>>>>>>>>>> we
> > >>>>>>>>>>>>>>>>>> can definitely make the Flink SQL DDL better.
> > >>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>> As @shaoxuan suggest, Jark can come up with a doc that
> > >>> talks
> > >>>>>>>>>>>>> about
> > >>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>> current DDL design in Alibaba, and we can discuss and
> > >>> merge
> > >>>>>>> them
> > >>>>>>>>>>>>>> into
> > >>>>>>>>>>>>>>>>> one,
> > >>>>>>>>>>>>>>>>>> make it as a FLIP, and plan the tasks for
> > >> implementation.
> > >>>>>>> Also,
> > >>>>>>>>>>>>> we
> > >>>>>>>>>>>>>>>> should
> > >>>>>>>>>>>>>>>>>> take into account the new external catalog effort in
> the
> > >>>>>>> design.
> > >>>>>>>>>>>>>> What
> > >>>>>>>>>>>>>>>> do
> > >>>>>>>>>>>>>>>>>> you guys think?
> > >>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>> Shuyi
> > >>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 6:45 AM Jark Wu <
> > >> [hidden email]
> > >>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>>> Hi Shaoxuan,
> > >>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>> I think summarizing it into a google doc is a good
> > >> idea.
> > >>> We
> > >>>>>>>>>>>>> will
> > >>>>>>>>>>>>>>>>> prepare
> > >>>>>>>>>>>>>>>>>> it
> > >>>>>>>>>>>>>>>>>>> in the next few days.
> > >>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>> Thanks,
> > >>>>>>>>>>>>>>>>>>> Jark
> > >>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>> Shaoxuan Wang <[hidden email]> 于2018年11月28日周三
> > >>>>>> 下午9:17写道：
> > >>>>>>>>>>>>>>>>>>>> Hi Lin and Jark,
> > >>>>>>>>>>>>>>>>>>>> Thanks for sharing those details. Can you please
> > >>> consider
> > >>>>>>>>>>>>>>>> summarizing
> > >>>>>>>>>>>>>>>>>>> your
> > >>>>>>>>>>>>>>>>>>>> DDL design into a google doc.
> > >>>>>>>>>>>>>>>>>>>> We can still continue the discussions on Shuyi's
> > >>> proposal.
> > >>>>>>>>>>>>> But
> > >>>>>>>>>>>>>>>>> having a
> > >>>>>>>>>>>>>>>>>>>> separate google doc will be easy for the DEV to
> > >>>>>>>>>>>>>>>>>>> understand/comment/discuss
> > >>>>>>>>>>>>>>>>>>>> on your proposed DDL implementation.
> > >>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>> Regards,
> > >>>>>>>>>>>>>>>>>>>> Shaoxuan
> > >>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 7:39 PM Jark Wu <
> > >>> [hidden email]
> > >>>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>> Thanks for bringing up this discussion and the
> > >> awesome
> > >>>>>>>>>>>>> work!
> > >>>>>>>>>>>>>> I
> > >>>>>>>>>>>>>>>> have
> > >>>>>>>>>>>>>>>>>>> left
> > >>>>>>>>>>>>>>>>>>>>> some comments in the doc.
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>> I want to share something more about the watermark
> > >>>>>>>>>>>>> definition
> > >>>>>>>>>>>>>>>>> learned
> > >>>>>>>>>>>>>>>>>>>> from
> > >>>>>>>>>>>>>>>>>>>>> Alibaba.
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>        1.
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>        Table should be able to accept multiple
> > >> watermark
> > >>>>>>>>>>>>>>> definition.
> > >>>>>>>>>>>>>>>>>>>>>        Because a table may have more than one
> rowtime
> > >>>>>> field.
> > >>>>>>>>>>>>> For
> > >>>>>>>>>>>>>>>>> example,
> > >>>>>>>>>>>>>>>>>>> one
> > >>>>>>>>>>>>>>>>>>>>>        rowtime field is from existing field but
> > >> missing
> > >>> in
> > >>>>>>> some
> > >>>>>>>>>>>>>>>>> records,
> > >>>>>>>>>>>>>>>>>>>>> another
> > >>>>>>>>>>>>>>>>>>>>>        is the ingestion timestamp in Kafka but not
> > >> very
> > >>>>>>>>>>>>> accurate.
> > >>>>>>>>>>>>>>> In
> > >>>>>>>>>>>>>>>>> this
> > >>>>>>>>>>>>>>>>>>>> case,
> > >>>>>>>>>>>>>>>>>>>>>        user may define two rowtime fields with
> > >>> watermarks
> > >>>>>> in
> > >>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>> Table
> > >>>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>> choose
> > >>>>>>>>>>>>>>>>>>>>>        one in different situation.
> > >>>>>>>>>>>>>>>>>>>>>        2.
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>        Watermark stragety always work with rowtime
> > >> field
> > >>>>>>>>>>>>>> together.
> > >>>>>>>>>>>>>>>>>>>>> Based on the two points metioned above, I think we
> > >>> should
> > >>>>>>>>>>>>>>> combine
> > >>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>> watermark strategy and rowtime field selection
> (i.e.
> > >>>>>> which
> > >>>>>>>>>>>>>>>> existing
> > >>>>>>>>>>>>>>>>>>> field
> > >>>>>>>>>>>>>>>>>>>>> used to generate watermark) in one clause, so that
> we
> > >>> can
> > >>>>>>>>>>>>>>> define
> > >>>>>>>>>>>>>>>>>>> multiple
> > >>>>>>>>>>>>>>>>>>>>> watermarks in one Table.
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>> Here I will share the watermark syntax used in
> > >> Alibaba
> > >>>>>>>>>>>>>> (simply
> > >>>>>>>>>>>>>>>>>>> modified):
> > >>>>>>>>>>>>>>>>>>>>> watermarkDefinition:
> > >>>>>>>>>>>>>>>>>>>>> WATERMARK [watermarkName] FOR <rowtime_field> AS
> > >>>>>>>>>>>>> wm_strategy
> > >>>>>>>>>>>>>>>>>>>>> wm_strategy:
> > >>>>>>>>>>>>>>>>>>>>>       BOUNDED WITH OFFSET 'string' timeUnit
> > >>>>>>>>>>>>>>>>>>>>> |
> > >>>>>>>>>>>>>>>>>>>>>       ASCENDING
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>> The “WATERMARK” keyword starts a watermark
> > >> definition.
> > >>>>>> The
> > >>>>>>>>>>>>>>> “FOR”
> > >>>>>>>>>>>>>>>>>>> keyword
> > >>>>>>>>>>>>>>>>>>>>> defines which existing field used to generate
> > >>> watermark,
> > >>>>>>>>>>>>> this
> > >>>>>>>>>>>>>>>> field
> > >>>>>>>>>>>>>>>>>>>> should
> > >>>>>>>>>>>>>>>>>>>>> already exist in the schema (we can use
> > >> computed-column
> > >>>>>> to
> > >>>>>>>>>>>>>>> derive
> > >>>>>>>>>>>>>>>>>> from
> > >>>>>>>>>>>>>>>>>>>>> other fields). The “AS” keyword defines watermark
> > >>>>>> strategy,
> > >>>>>>>>>>>>>>> such
> > >>>>>>>>>>>>>>>> as
> > >>>>>>>>>>>>>>>>>>>> BOUNDED
> > >>>>>>>>>>>>>>>>>>>>> WITH OFFSET (covers almost all the requirements)
> and
> > >>>>>>>>>>>>>> ASCENDING.
> > >>>>>>>>>>>>>>>>>>>>> When the expected rowtime field does not exist in
> the
> > >>>>>>>>>>>>> schema,
> > >>>>>>>>>>>>>>> we
> > >>>>>>>>>>>>>>>>> can
> > >>>>>>>>>>>>>>>>>>> use
> > >>>>>>>>>>>>>>>>>>>>> computed-column syntax to derive it from other
> > >> existing
> > >>>>>>>>>>>>>> fields
> > >>>>>>>>>>>>>>>>> using
> > >>>>>>>>>>>>>>>>>>>>> built-in functions or user defined functions. So
> the
> > >>>>>>>>>>>>>>>>>> rowtime/watermark
> > >>>>>>>>>>>>>>>>>>>>> definition doesn’t need to care about
> “field-change”
> > >>>>>>>>>>>>> strategy
> > >>>>>>>>>>>>>>>>>>>>> (replace/add/from-field). And the proctime field
> > >>>>>> definition
> > >>>>>>>>>>>>>> can
> > >>>>>>>>>>>>>>>>> also
> > >>>>>>>>>>>>>>>>>> be
> > >>>>>>>>>>>>>>>>>>>>> defined using computed-column. Such as pt as
> > >> PROCTIME()
> > >>>>>>>>>>>>> which
> > >>>>>>>>>>>>>>>>>> defines a
> > >>>>>>>>>>>>>>>>>>>>> proctime field named “pt” in the schema.
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>> Looking forward to working with you guys!
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>> Best,
> > >>>>>>>>>>>>>>>>>>>>> Jark Wu
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>> Lin Li <[hidden email]> 于2018年11月28日周三
> > >>> 下午6:33写道：
> > >>>>>>>>>>>>>>>>>>>>>> @Shuyi
> > >>>>>>>>>>>>>>>>>>>>>> Thanks for the proposal!  We have a simple DDL
> > >>>>>>>>>>>>>> implementation
> > >>>>>>>>>>>>>>>>>>> (extends
> > >>>>>>>>>>>>>>>>>>>>>> Calcite's parser) which been running for almost
> two
> > >>>>>> years
> > >>>>>>>>>>>>>> on
> > >>>>>>>>>>>>>>>>>>> production
> > >>>>>>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>>> works well.
> > >>>>>>>>>>>>>>>>>>>>>> I think the most valued things we'd learned is
> > >> keeping
> > >>>>>>>>>>>>>>>> simplicity
> > >>>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>>> standard compliance.
> > >>>>>>>>>>>>>>>>>>>>>> Here's the approximate grammar, FYI
> > >>>>>>>>>>>>>>>>>>>>>> CREATE TABLE
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> CREATE TABLE tableName(
> > >>>>>>>>>>>>>>>>>>>>>>             columnDefinition [, columnDefinition]*
> > >>>>>>>>>>>>>>>>>>>>>>             [ computedColumnDefinition [,
> > >>>>>>>>>>>>>>>> computedColumnDefinition]*
> > >>>>>>>>>>>>>>>>> ]
> > >>>>>>>>>>>>>>>>>>>>>>             [ tableConstraint [,
> tableConstraint]* ]
> > >>>>>>>>>>>>>>>>>>>>>>             [ tableIndex [, tableIndex]* ]
> > >>>>>>>>>>>>>>>>>>>>>>         [ PERIOD FOR SYSTEM_TIME ]
> > >>>>>>>>>>>>>>>>>>>>>>             [ WATERMARK watermarkName FOR
> > >> rowTimeColumn
> > >>>> AS
> > >>>>>>>>>>>>>>>>>>>>>> withOffset(rowTimeColumn, offset) ]     ) [ WITH (
> > >>>>>>>>>>>>>>> tableOption
> > >>>>>>>>>>>>>>>> [
> > >>>>>>>>>>>>>>>>> ,
> > >>>>>>>>>>>>>>>>>>>>>> tableOption]* ) ] [ ; ]
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> columnDefinition ::=
> > >>>>>>>>>>>>>>>>>>>>>>             columnName dataType [ NOT NULL ]
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> dataType  ::=
> > >>>>>>>>>>>>>>>>>>>>>>             {
> > >>>>>>>>>>>>>>>>>>>>>>               [ VARCHAR ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ BOOLEAN ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ TINYINT ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ SMALLINT ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ INT ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ BIGINT ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ FLOAT ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ DECIMAL ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ DOUBLE ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ DATE ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ TIME ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ TIMESTAMP ]
> > >>>>>>>>>>>>>>>>>>>>>>               | [ VARBINARY ]
> > >>>>>>>>>>>>>>>>>>>>>>             }
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> computedColumnDefinition ::=
> > >>>>>>>>>>>>>>>>>>>>>>             columnName AS computedColumnExpression
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> tableConstraint ::=
> > >>>>>>>>>>>>>>>>>>>>>>         { PRIMARY KEY | UNIQUE }
> > >>>>>>>>>>>>>>>>>>>>>>             (columnName [, columnName]* )
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> tableIndex ::=
> > >>>>>>>>>>>>>>>>>>>>>>             [ UNIQUE ] INDEX indexName
> > >>>>>>>>>>>>>>>>>>>>>>              (columnName [, columnName]* )
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> rowTimeColumn ::=
> > >>>>>>>>>>>>>>>>>>>>>>             columnName
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> tableOption ::=
> > >>>>>>>>>>>>>>>>>>>>>>             property=value
> > >>>>>>>>>>>>>>>>>>>>>>             offset ::=
> > >>>>>>>>>>>>>>>>>>>>>>             positive integer (unit: ms)
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> CREATE VIEW
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> CREATE VIEW viewName
> > >>>>>>>>>>>>>>>>>>>>>>       [
> > >>>>>>>>>>>>>>>>>>>>>>             ( columnName [, columnName]* )
> > >>>>>>>>>>>>>>>>>>>>>>       ]
> > >>>>>>>>>>>>>>>>>>>>>>             AS queryStatement;
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> CREATE FUNCTION
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>      CREATE FUNCTION functionName
> > >>>>>>>>>>>>>>>>>>>>>>       AS 'className';
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>      className ::=
> > >>>>>>>>>>>>>>>>>>>>>>             fully qualified name
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>> Shuyi Chen <[hidden email]> 于2018年11月28日周三
> > >>>>>> 上午3:28写道：
> > >>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Timo and Xuefu. Yes, I think we can
> > >>>>>>>>>>>>>> finalize
> > >>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>> design
> > >>>>>>>>>>>>>>>>>>>>> doc
> > >>>>>>>>>>>>>>>>>>>>>>> first and start implementation w/o the unified
> > >>>>>>>>>>>>> connector
> > >>>>>>>>>>>>>>> API
> > >>>>>>>>>>>>>>>>>> ready
> > >>>>>>>>>>>>>>>>>>> by
> > >>>>>>>>>>>>>>>>>>>>>>> skipping some featue.
> > >>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>> Xuefu, I like the idea of making Flink specific
> > >>>>>>>>>>>>>> properties
> > >>>>>>>>>>>>>>>> into
> > >>>>>>>>>>>>>>>>>>>> generic
> > >>>>>>>>>>>>>>>>>>>>>>> key-value pairs, so that it will make integration
> > >>> with
> > >>>>>>>>>>>>>> Hive
> > >>>>>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>>> (or
> > >>>>>>>>>>>>>>>>>>>>>> others,
> > >>>>>>>>>>>>>>>>>>>>>>> e.g. Beam DDL) easier.
> > >>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>> I'll run a final pass over the design doc and
> > >>> finalize
> > >>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>> design
> > >>>>>>>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>> next few days. And we can start creating tasks
> and
> > >>>>>>>>>>>>>>>> collaborate
> > >>>>>>>>>>>>>>>>> on
> > >>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>> implementation. Thanks a lot for all the comments
> > >> and
> > >>>>>>>>>>>>>>> inputs.
> > >>>>>>>>>>>>>>>>>>>>>>> Cheers!
> > >>>>>>>>>>>>>>>>>>>>>>> Shuyi
> > >>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>> On Tue, Nov 27, 2018 at 7:02 AM Zhang, Xuefu <
> > >>>>>>>>>>>>>>>>>>>> [hidden email]>
> > >>>>>>>>>>>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> Yeah! I agree with Timo that DDL can actually
> > >>> proceed
> > >>>>>>>>>>>>>> w/o
> > >>>>>>>>>>>>>>>>> being
> > >>>>>>>>>>>>>>>>>>>>> blocked
> > >>>>>>>>>>>>>>>>>>>>>>> by
> > >>>>>>>>>>>>>>>>>>>>>>>> connector API. We can leave the unknown out
> while
> > >>>>>>>>>>>>>>> defining
> > >>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>> basic
> > >>>>>>>>>>>>>>>>>>>>>>> syntax.
> > >>>>>>>>>>>>>>>>>>>>>>>> @Shuyi
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> As commented in the doc, I think we can probably
> > >>>>>>>>>>>>> stick
> > >>>>>>>>>>>>>>> with
> > >>>>>>>>>>>>>>>>>>> simple
> > >>>>>>>>>>>>>>>>>>>>>> syntax
> > >>>>>>>>>>>>>>>>>>>>>>>> with general properties, without extending the
> > >>> syntax
> > >>>>>>>>>>>>>> too
> > >>>>>>>>>>>>>>>>> much
> > >>>>>>>>>>>>>>>>>>> that
> > >>>>>>>>>>>>>>>>>>>>> it
> > >>>>>>>>>>>>>>>>>>>>>>>> mimics the descriptor API.
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> Part of our effort on Flink-Hive integration is
> > >> also
> > >>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>> make
> > >>>>>>>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>>>>>> syntax
> > >>>>>>>>>>>>>>>>>>>>>>>> compatible with Hive's. The one in the current
> > >>>>>>>>>>>>> proposal
> > >>>>>>>>>>>>>>>> seems
> > >>>>>>>>>>>>>>>>>>>> making
> > >>>>>>>>>>>>>>>>>>>>>> our
> > >>>>>>>>>>>>>>>>>>>>>>>> effort more challenging.
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> We can help and collaborate. At this moment, I
> > >> think
> > >>>>>>>>>>>>> we
> > >>>>>>>>>>>>>>> can
> > >>>>>>>>>>>>>>>>>>>> finalize
> > >>>>>>>>>>>>>>>>>>>>> on
> > >>>>>>>>>>>>>>>>>>>>>>>> the proposal and then we can divide the tasks
> for
> > >>>>>>>>>>>>>> better
> > >>>>>>>>>>>>>>>>>>>>> collaboration.
> > >>>>>>>>>>>>>>>>>>>>>>>> Please let me know if there are  any questions
> or
> > >>>>>>>>>>>>>>>>> suggestions.
> > >>>>>>>>>>>>>>>>>>>>>>>> Thanks,
> > >>>>>>>>>>>>>>>>>>>>>>>> Xuefu
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>> ------------------------------------------------------------------
> > >>>>>>>>>>>>>>>>>>>>>>>> Sender:Timo Walther <[hidden email]>
> > >>>>>>>>>>>>>>>>>>>>>>>> Sent at:2018 Nov 27 (Tue) 16:21
> > >>>>>>>>>>>>>>>>>>>>>>>> Recipient:dev <[hidden email]>
> > >>>>>>>>>>>>>>>>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> Thanks for offering your help here, Xuefu. It
> > >> would
> > >>>>>>>>>>>>> be
> > >>>>>>>>>>>>>>>> great
> > >>>>>>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>>>>>> move
> > >>>>>>>>>>>>>>>>>>>>>>>> these efforts forward. I agree that the DDL is
> > >>>>>>>>>>>>> somehow
> > >>>>>>>>>>>>>>>>> releated
> > >>>>>>>>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>>> unified connector API design but we can also
> start
> > >>>>>>>>>>>>> with
> > >>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>> basic
> > >>>>>>>>>>>>>>>>>>>>>>>> functionality now and evolve the DDL during this
> > >>>>>>>>>>>>>> release
> > >>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>> next
> > >>>>>>>>>>>>>>>>>>>>>>> releases.
> > >>>>>>>>>>>>>>>>>>>>>>>> For example, we could identify the MVP DDL
> syntax
> > >>>>>>>>>>>>> that
> > >>>>>>>>>>>>>>>> skips
> > >>>>>>>>>>>>>>>>>>>> defining
> > >>>>>>>>>>>>>>>>>>>>>>>> key constraints and maybe even time attributes.
> > >> This
> > >>>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>> could
> > >>>>>>>>>>>>>>>>>> be
> > >>>>>>>>>>>>>>>>>>>>> used
> > >>>>>>>>>>>>>>>>>>>>>>>> for batch usecases, ETL, and materializing SQL
> > >>>>>>>>>>>>> queries
> > >>>>>>>>>>>>>>> (no
> > >>>>>>>>>>>>>>>>> time
> > >>>>>>>>>>>>>>>>>>>>>>>> operations like windows).
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> The unified connector API is high on our
> priority
> > >>>>>>>>>>>>> list
> > >>>>>>>>>>>>>>> for
> > >>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>> 1.8
> > >>>>>>>>>>>>>>>>>>>>>>>> release. I will try to update the document until
> > >> mid
> > >>>>>>>>>>>>> of
> > >>>>>>>>>>>>>>>> next
> > >>>>>>>>>>>>>>>>>>> week.
> > >>>>>>>>>>>>>>>>>>>>>>>> Regards,
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> Timo
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>> Am 27.11.18 um 08:08 schrieb Shuyi Chen:
> > >>>>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Xuefu. I was busy for some other
> > >>>>>>>>>>>>> stuff
> > >>>>>>>>>>>>>>> for
> > >>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>> last 2
> > >>>>>>>>>>>>>>>>>>>>>>>> weeks,
> > >>>>>>>>>>>>>>>>>>>>>>>>> but we are definitely interested in moving this
> > >>>>>>>>>>>>>>> forward.
> > >>>>>>>>>>>>>>>> I
> > >>>>>>>>>>>>>>>>>>> think
> > >>>>>>>>>>>>>>>>>>>>> once
> > >>>>>>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>>>> unified connector API design [1] is done, we
> can
> > >>>>>>>>>>>>>>> finalize
> > >>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>>>>>>>> design
> > >>>>>>>>>>>>>>>>>>>>>>>> as
> > >>>>>>>>>>>>>>>>>>>>>>>>> well and start creating concrete subtasks to
> > >>>>>>>>>>>>>>> collaborate
> > >>>>>>>>>>>>>>>> on
> > >>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>>>> implementation with the community.
> > >>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>> Shuyi
> > >>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > >>>>>>>>>>>>>>>>>>>>>>>>>
> > >>
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> > >>>>>>>>>>>>>>>>>>>>>>>>> On Mon, Nov 26, 2018 at 7:01 PM Zhang, Xuefu <
> > >>>>>>>>>>>>>>>>>>>>>> [hidden email]>
> > >>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> I'm wondering if you folks still have the
> > >>>>>>>>>>>>> bandwidth
> > >>>>>>>>>>>>>>>>> working
> > >>>>>>>>>>>>>>>>>> on
> > >>>>>>>>>>>>>>>>>>>>> this.
> > >>>>>>>>>>>>>>>>>>>>>>>>>> We have some dedicated resource and like to
> move
> > >>>>>>>>>>>>>> this
> > >>>>>>>>>>>>>>>>>> forward.
> > >>>>>>>>>>>>>>>>>>>> We
> > >>>>>>>>>>>>>>>>>>>>>> can
> > >>>>>>>>>>>>>>>>>>>>>>>>>> collaborate.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> Thanks,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>
> ------------------------------------------------------------------
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 发件人：wenlong.lwl<[hidden email]>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 日 期：2018年11月05日 11:15:35
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 收件人：<[hidden email]>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 主 题：Re: [DISCUSS] Flink SQL DDL Design
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> Hi, Shuyi, thanks for the proposal.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> I have two concerns about the table ddl:
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 1. how about remove the source/sink mark from
> > >> the
> > >>>>>>>>>>>>>> ddl,
> > >>>>>>>>>>>>>>>>>> because
> > >>>>>>>>>>>>>>>>>>>> it
> > >>>>>>>>>>>>>>>>>>>>> is
> > >>>>>>>>>>>>>>>>>>>>>>> not
> > >>>>>>>>>>>>>>>>>>>>>>>>>> necessary, the framework determine the table
> > >>>>>>>>>>>>>> referred
> > >>>>>>>>>>>>>>>> is a
> > >>>>>>>>>>>>>>>>>>>> source
> > >>>>>>>>>>>>>>>>>>>>>> or a
> > >>>>>>>>>>>>>>>>>>>>>>>> sink
> > >>>>>>>>>>>>>>>>>>>>>>>>>> according to the context of the query using
> the
> > >>>>>>>>>>>>>> table.
> > >>>>>>>>>>>>>>>> it
> > >>>>>>>>>>>>>>>>>> will
> > >>>>>>>>>>>>>>>>>>>> be
> > >>>>>>>>>>>>>>>>>>>>>> more
> > >>>>>>>>>>>>>>>>>>>>>>>>>> convenient for use defining a table which can
> be
> > >>>>>>>>>>>>>> both
> > >>>>>>>>>>>>>>> a
> > >>>>>>>>>>>>>>>>>> source
> > >>>>>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>>>> sink,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> and more convenient for catalog to persistent
> > >> and
> > >>>>>>>>>>>>>>> manage
> > >>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>> meta
> > >>>>>>>>>>>>>>>>>>>>>>> infos.
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 2. how about just keeping one pure string map
> as
> > >>>>>>>>>>>>>>>>> parameters
> > >>>>>>>>>>>>>>>>>>> for
> > >>>>>>>>>>>>>>>>>>>>>> table,
> > >>>>>>>>>>>>>>>>>>>>>>>> like
> > >>>>>>>>>>>>>>>>>>>>>>>>>> create tabe Kafka10SourceTable (
> > >>>>>>>>>>>>>>>>>>>>>>>>>> intField INTEGER,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> stringField VARCHAR(128),
> > >>>>>>>>>>>>>>>>>>>>>>>>>> longField BIGINT,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> rowTimeField TIMESTAMP
> > >>>>>>>>>>>>>>>>>>>>>>>>>> ) with (
> > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.type = ’kafka’,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.property-version = ’1’,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.version = ’0.10’,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.topic =
> ‘test-kafka-topic’,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.startup-mode =
> > >>>>>>>>>>>>> ‘latest-offset’,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.specific-offset =
> ‘offset’,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> format.type = 'json'
> > >>>>>>>>>>>>>>>>>>>>>>>>>> format.prperties.version=’1’,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> format.derive-schema = 'true'
> > >>>>>>>>>>>>>>>>>>>>>>>>>> );
> > >>>>>>>>>>>>>>>>>>>>>>>>>> Because:
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 1. in TableFactory, what user use is a string
> > >> map
> > >>>>>>>>>>>>>>>>>> properties,
> > >>>>>>>>>>>>>>>>>>>>>> defining
> > >>>>>>>>>>>>>>>>>>>>>>>>>> parameters by string-map can be the closest
> way
> > >> to
> > >>>>>>>>>>>>>>>> mapping
> > >>>>>>>>>>>>>>>>>> how
> > >>>>>>>>>>>>>>>>>>>>> user
> > >>>>>>>>>>>>>>>>>>>>>>> use
> > >>>>>>>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>>>>> parameters.
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 2. The table descriptor can be extended by
> user,
> > >>>>>>>>>>>>>> like
> > >>>>>>>>>>>>>>>> what
> > >>>>>>>>>>>>>>>>>> is
> > >>>>>>>>>>>>>>>>>>>> done
> > >>>>>>>>>>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>>>>>>>>> Kafka
> > >>>>>>>>>>>>>>>>>>>>>>>>>> and Json, it means that the parameter keys in
> > >>>>>>>>>>>>>>> connector
> > >>>>>>>>>>>>>>>> or
> > >>>>>>>>>>>>>>>>>>>> format
> > >>>>>>>>>>>>>>>>>>>>>> can
> > >>>>>>>>>>>>>>>>>>>>>>> be
> > >>>>>>>>>>>>>>>>>>>>>>>>>> different in different implementation, we can
> > >> not
> > >>>>>>>>>>>>>>>> restrict
> > >>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>> key
> > >>>>>>>>>>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>>>>>>>> a
> > >>>>>>>>>>>>>>>>>>>>>>>>>> specified set, so we need a map in connector
> > >> scope
> > >>>>>>>>>>>>>>> and a
> > >>>>>>>>>>>>>>>>> map
> > >>>>>>>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties scope. why not just give
> > >>>>>>>>>>>>> user a
> > >>>>>>>>>>>>>>>>> single
> > >>>>>>>>>>>>>>>>>>> map,
> > >>>>>>>>>>>>>>>>>>>>> let
> > >>>>>>>>>>>>>>>>>>>>>>>> them
> > >>>>>>>>>>>>>>>>>>>>>>>>>> put parameters in a format they like, which is
> > >>>>>>>>>>>>> also
> > >>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>> simplest
> > >>>>>>>>>>>>>>>>>>>>> way
> > >>>>>>>>>>>>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>>>>>>>>>>>> implement DDL parser.
> > >>>>>>>>>>>>>>>>>>>>>>>>>> 3. whether we can define a format clause or
> not,
> > >>>>>>>>>>>>>>> depends
> > >>>>>>>>>>>>>>>>> on
> > >>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>>>>> implementation of the connector, using
> different
> > >>>>>>>>>>>>>>> clause
> > >>>>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>>>>> may
> > >>>>>>>>>>>>>>>>>>>>>>> make
> > >>>>>>>>>>>>>>>>>>>>>>>> a
> > >>>>>>>>>>>>>>>>>>>>>>>>>> misunderstanding that we can combine the
> > >>>>>>>>>>>>> connectors
> > >>>>>>>>>>>>>>> with
> > >>>>>>>>>>>>>>>>>>>> arbitrary
> > >>>>>>>>>>>>>>>>>>>>>>>> formats,
> > >>>>>>>>>>>>>>>>>>>>>>>>>> which may not work actually.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>> On Sun, 4 Nov 2018 at 18:25, Dominik Wosiński
> <
> > >>>>>>>>>>>>>>>>>>> [hidden email]
> > >>>>>>>>>>>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> +1, Thanks for the proposal.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> I guess this is a long-awaited change. This
> can
> > >>>>>>>>>>>>>>> vastly
> > >>>>>>>>>>>>>>>>>>> increase
> > >>>>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> functionalities of the SQL Client as it will
> be
> > >>>>>>>>>>>>>>>> possible
> > >>>>>>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>>>>> use
> > >>>>>>>>>>>>>>>>>>>>>>> complex
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> extensions like for example those provided by
> > >>>>>>>>>>>>>> Apache
> > >>>>>>>>>>>>>>>>>>> Bahir[1].
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> Best Regards,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> Dom.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> https://github.com/apache/bahir-flink
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> sob., 3 lis 2018 o 17:17 Rong Rong <
> > >>>>>>>>>>>>>>>> [hidden email]>
> > >>>>>>>>>>>>>>>>>>>>>> napisał(a):
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> +1. Thanks for putting the proposal together
> > >>>>>>>>>>>>>> Shuyi.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL has been brought up in a couple of times
> > >>>>>>>>>>>>>>>> previously
> > >>>>>>>>>>>>>>>>>>> [1,2].
> > >>>>>>>>>>>>>>>>>>>>>>>>>> Utilizing
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL will definitely be a great extension to
> > >> the
> > >>>>>>>>>>>>>>>> current
> > >>>>>>>>>>>>>>>>>>> Flink
> > >>>>>>>>>>>>>>>>>>>>> SQL
> > >>>>>>>>>>>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> systematically support some of the
> previously
> > >>>>>>>>>>>>>>> brought
> > >>>>>>>>>>>>>>>> up
> > >>>>>>>>>>>>>>>>>>>>> features
> > >>>>>>>>>>>>>>>>>>>>>>> such
> > >>>>>>>>>>>>>>>>>>>>>>>>>> as
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]. And it will also be beneficial to see
> the
> > >>>>>>>>>>>>>>>> document
> > >>>>>>>>>>>>>>>>>>>> closely
> > >>>>>>>>>>>>>>>>>>>>>>>> aligned
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> with the previous discussion for unified SQL
> > >>>>>>>>>>>>>>> connector
> > >>>>>>>>>>>>>>>>> API
> > >>>>>>>>>>>>>>>>>>>> [4].
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> I also left a few comments on the doc.
> Looking
> > >>>>>>>>>>>>>>> forward
> > >>>>>>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>>>>>>> alignment
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> with the other couple of efforts and
> > >>>>>>>>>>>>> contributing
> > >>>>>>>>>>>>>> to
> > >>>>>>>>>>>>>>>>> them!
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> Best,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> Rong
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201805.mbox/%3CCAMZk55ZTJA7MkCK1Qu4gLPu1P9neqCfHZtTcgLfrFjfO4Xv5YQ%40mail.gmail.com%3E
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3CDC070534-0782-4AFD-8A85-8A82B384B8F7%40gmail.com%3E
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
> > >>>>>>>>>>>>>>> https://issues.apache.org/jira/browse/FLINK-8003
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [4]
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3C6676cb66-6f31-23e1-eff5-2e9c19f88483@...%3E
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> On Fri, Nov 2, 2018 at 10:22 AM Bowen Li <
> > >>>>>>>>>>>>>>>>>>> [hidden email]
> > >>>>>>>>>>>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks Shuyi!
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> I left some comments there. I think the
> > >> design
> > >>>>>>>>>>>>> of
> > >>>>>>>>>>>>>>> SQL
> > >>>>>>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> Flink-Hive
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration/External catalog enhancements
> > >> will
> > >>>>>>>>>>>>>> work
> > >>>>>>>>>>>>>>>>>> closely
> > >>>>>>>>>>>>>>>>>>>>> with
> > >>>>>>>>>>>>>>>>>>>>>>> each
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> other. Hope we are well aligned on the
> > >>>>>>>>>>>>> directions
> > >>>>>>>>>>>>>>> of
> > >>>>>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>> two
> > >>>>>>>>>>>>>>>>>>>>>>> designs,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> and I
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> look forward to working with you guys on
> > >> both!
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bowen
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Thu, Nov 1, 2018 at 10:57 PM Shuyi Chen
> <
> > >>>>>>>>>>>>>>>>>>>> [hidden email]
> > >>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi everyone,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL DDL support has been a long-time ask
> > >> from
> > >>>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>>> community.
> > >>>>>>>>>>>>>>>>>>>>>>>>>> Current
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Flink
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL support only DML (e.g. SELECT and
> INSERT
> > >>>>>>>>>>>>>>>>>> statements).
> > >>>>>>>>>>>>>>>>>>> In
> > >>>>>>>>>>>>>>>>>>>>> its
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> current
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> form, Flink SQL users still need to
> > >>>>>>>>>>>>>> define/create
> > >>>>>>>>>>>>>>>>> table
> > >>>>>>>>>>>>>>>>>>>>> sources
> > >>>>>>>>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> sinks
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> programmatically in Java/Scala. Also, in
> SQL
> > >>>>>>>>>>>>>>> Client,
> > >>>>>>>>>>>>>>>>>>> without
> > >>>>>>>>>>>>>>>>>>>>> DDL
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> support,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the current implementation does not allow
> > >>>>>>>>>>>>>>> dynamical
> > >>>>>>>>>>>>>>>>>>> creation
> > >>>>>>>>>>>>>>>>>>>>> of
> > >>>>>>>>>>>>>>>>>>>>>>>>>>> table,
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> type
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> or functions with SQL, this adds friction
> > >> for
> > >>>>>>>>>>>>>> its
> > >>>>>>>>>>>>>>>>>>> adoption.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I drafted a design doc [1] with a few
> other
> > >>>>>>>>>>>>>>>> community
> > >>>>>>>>>>>>>>>>>>>> members
> > >>>>>>>>>>>>>>>>>>>>>> that
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> proposes
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the design and implementation for adding
> DDL
> > >>>>>>>>>>>>>>> support
> > >>>>>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>>>>> Flink.
> > >>>>>>>>>>>>>>>>>>>>>> The
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> initial
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> design considers DDL for table, view,
> type,
> > >>>>>>>>>>>>>>> library
> > >>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>>> function.
> > >>>>>>>>>>>>>>>>>>>>>>>>>> It
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> will
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> be great to get feedback on the design
> from
> > >>>>>>>>>>>>> the
> > >>>>>>>>>>>>>>>>>> community,
> > >>>>>>>>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>>>>>>>>>>> align
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> with
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> latest effort in unified SQL connector API
> > >> [2]
> > >>>>>>>>>>>>>> and
> > >>>>>>>>>>>>>>>>> Flink
> > >>>>>>>>>>>>>>>>>>>> Hive
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3].
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Any feedback is highly appreciated.
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi Chen
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>
> >
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit?usp=sharing
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > >>
> >
> https://docs.google.com/document/d/1SkppRD_rE3uOKSN-LuZCqn4f7dz0zW5aa6T_hBZq5_o/edit?usp=sharing
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> --
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
> > >>>>>>>>>>>>> somehow
> > >>>>>>>>>>>>>>>>> connect
> > >>>>>>>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>>>>>> your
> > >>>>>>>>>>>>>>>>>>>>>>>>>>>> future."
> > >>>>>>>>>>>>>>>>>>>>>>> --
> > >>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow
> > >>>>>>>>>>>>> connect
> > >>>>>>>>>>>>>> in
> > >>>>>>>>>>>>>>>>> your
> > >>>>>>>>>>>>>>>>>>>>> future."
> > >>>>>>>>>>>>>>>>>> --
> > >>>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow
> connect
> > >>> in
> > >>>>>>> your
> > >>>>>>>>>>>>>>>> future."
> > >>>>>>>>>>>>> --
> > >>>>>>>>>>>>> "So you have to trust that the dots will somehow connect in
> > >>> your
> > >>>>>>>>>>> future."
> > >>>>>>>>>>>
> > >>>>
> > >>> --
> > >>> "So you have to trust that the dots will somehow connect in your
> > future."
> > >>>
> >
> >
>
> --
> "So you have to trust that the dots will somehow connect in your future."
>

[Jark Wu-2]

Hi all,

Here are a bunch of my thoughts:

8). support row/map/array data type
That's fine with me if we want to support them in the MVP. In my mind, we
can have the field type syntax like this:

```
filedType ::=
            {
                simpleType
             | MAP<simpleType, fieldType>
             | ARRAY<fieldType>
             | ROW<columnDefinition [, columnDefinition]*>
            }
```

I have included this in @Shuyi's summary doc [1] . Please leave feedbacks
there!

[1]
https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit

3) SOURCE / SINK / BOTH
@Timo, CREATE TABLE statement is registering a virtual table in the session
or catalog. I don't think it is immutable, as we might also want to support
CREATE INDEX statements in the future. On the other hand, ACL is not a part
of the table definition, it should belong to the permission system which is
usually stored in somewhere else. So GRANT/INVOKE sounds like a more
standard option.

7) Table Update Mode
I agree with @Shuyi that table update mode can be left out from the MVP.
Because IMO, the update mode will not break the current MVP design. It
should be something to add, like the CHANGE_FLAG you proposed. We can
continue this discussion when we finalize the MVP.

Meanwhile, the update mode is a big topic which may involve several weeks
to discuss. For example, (a) do we support CHANGE_FLAG when the table
supports upsert (or when the table defined a primary key)?  (b) the
CHANGE_FLAG should support write and read both. (c) currently, we only
support true (add) and false (retract) flag type, are they enough? (d) How
to connect an external storage which also support insert/delete flag like
mysql binlog?

Regarding to the CHANGE_FLAG @Timo proposed, I think this is a good
direction. But should isRetraction be a physical field and make CHANGE_FLAG
like a constraint on that? If yes, then what the type of isRetraction?

4.b) Ingesting and writing timestamps to systems.
@Shuyi, PERSISTED can solve the problem of the field is not physically
stored. However, it doesn't solve the problem that how to write a field
back to the computed column, because "A computed column cannot be the
target of an INSERT or UPDATE statement" even if the computed column is
persisted. If we want to write a rowtime back the the external system, the
DML should look like this: "INSERT INTO sink SELECT a, rowtime FROM
source". The point is that the `rowtime` must be specified in the INSERT
statement, that's why I hope the `rowtime` field in Table is not a computed
column. See more information about PERSISTED [2] [3].

Another point to consider is SYSTEMROWTIME() only solve reading timestamp
from message header in systems. There are many similar requirements here,
such as reading `topic`, `partition`, `offset` or custom properties from
message headers, do we plan to support a bunch of built-in functions like
SYSTEMROWTIME()?  Do we have some clean and easy way for this?

[2]:
https://docs.microsoft.com/en-us/sql/t-sql/statements/alter-table-computed-column-definition-transact-sql?view=sql-server-2017
[3]:
https://stackoverflow.com/questions/51390531/sql-server-persisted-computed-columns-versus-actual-normal-column

Looking forward to collaborate with you guys!

Best,
Jark


On Thu, 13 Dec 2018 at 01:38, Rong Rong <[hidden email]> wrote:

> Thanks for the summary effort @shuyi. Sorry for jumping in the discussion
> so late.
>
> As of the scope of MVP, I think we might want to consider adding "table
> update mode" problem to it. I agree with @timo that might not be easily
> changed in the future if the flags has to be part of the schema/column
> definition.
>
> Regarding the components under discussion.
> 4) Event-Time Attributes and Watermarks
> b, c) I actually like the special indicator way @fabian suggested to hint
> Flink to read time attributes directly from the system not the data `(ts AS
> SYSTEMROWTIME())`. It should also address the "compute field not emitted"
> problem by carrying the "virtual column" concept like @shuyi suggested.
> However if I understand correctly, this also required to be defined as part
> of the schema/column definition.
>
> 3) SOURCE / SINK / BOTH
> +1 on not adding properties to `CREATE TABLE` to manage ACL/permission.
>
> On a higher level, I think one question I have is whether we can
> definitively come to an agreement that the features under discussion (and
> potential solutions) can be cleanly adjusted/added from what we are
> providing on MVP (e.g. the schema/column definition might be hard to
> achieve but if we all agree ACL/permission should not be part of the
> `CREATE TABLE` and a decision can be made later). @shuyi I can also help in
> drafting the FLIP doc by summarizing the features under discussion and the
> concerns to whether included in the MVP, so that we can carry on the
> discussions alongside with the MVP implementation effort. I think each one
> of these features deserves a subsection dedicated for it.
>
> Many thanks,
> Rong
>
>
> On Wed, Dec 12, 2018 at 1:14 AM Shuyi Chen <[hidden email]> wrote:
>
> > Hi all,
> >
> > I summarize the MVP based on the features that we agreed upon. For table
> > update mode and custom watermark strategy and ts extractor, I found there
> > are some discussions, so I decided to leave them out for the MVP.
> > For row/map/array data type, I think we can add it as well if everyone
> > agrees.
> >
> >
> > 4) Event-Time Attributes and Watermarks
> > Cited from SQL Server 2017 document (
> >
> >
> https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2017
> > ),
> > "A
> > computed column is a virtual column that is not physically stored in the
> > table, unless the column is marked PERSISTED. A computed column
> expression
> > can use data from other columns to calculate a value for the column to
> > which it belongs. " I think we can also use introduce the PERSISTED
> keyword
> > for computed column to indicate that the field can be stored back to the
> > table, i.e. ts AS SYSTEMROWTIME() PERSISTED.
> >
> > 3) SOURCE / SINK / BOTH
> > GRANT/INVOKE sounds like a more standard option than adding a property to
> > CREATE TABLE to manage the ACL/permission. The ACL can be stored
> somewhere
> > in a database, and allow/disallow access to a dynamic table depending on
> > whether it's a "INSERT INTO" or "SELECT".
> >
> > I can volunteer to put the discussion as a FLIP.  I can try to summarize
> > the current discussion, and share edit permission with you to collaborate
> > on the documents. After we finalized the doc, we can publish it as a
> FLIP.
> > What do you think?
> >
> > Shuyi
> >
> >
> >
> > On Tue, Dec 11, 2018 at 9:13 AM Timo Walther <[hidden email]> wrote:
> >
> > > Hi all,
> > >
> > > thanks for summarizing the discussion @Shuyi. I think we need to
> include
> > > the "table update mode" problem as it might not be changed easily in
> the
> > > future. Regarding "support row/map/array data type", I don't see a
> > > problem why we should not support them now as the data types are
> already
> > > included in the runtime. The "support custom timestamp extractor" is
> > > solved by the computed columns approach. The "custom watermark
> strategy"
> > > can be added by supplying a class name as paramter in my opinion.
> > >
> > > Regarding the comments of Lin and Jark:
> > >
> > > @Lin: Instantiating a TableSource/Sink should not cost much, but we
> > > should not mix catalog discussion and DDL at this point.
> > >
> > > 4) Event-Time Attributes and Watermarks
> > > 4.b) Regarding `ts AS SYSTEMROWTIME()` and Lin's comment about "will
> > > violate the rule": there is no explicit rule of doing so. Computed
> > > column are also not standard compliant, if we can use information that
> > > is encoded in constraints we should use it. Adding more and more
> > > top-level properties makes the interaction with connectors more
> > > difficult. An additional HEADER keyword sounds too connector-specific
> > > and also not SQL compliant to me.
> > >
> > > 3) SOURCE / SINK / BOTH
> > > GRANT/INVOKE are mutating an existing table, right? In my opinion,
> > > independent of SQL databases but focusing on Flink user requirements, a
> > > CREATE TABLE statement should be an immutable definition of a
> connection
> > > to an external system.
> > >
> > > 7) Table Update Mode
> > > As far as I can see, the only thing missing for enabling all table
> modes
> > > is the declaration of a change flag. We could introduce a new keyword
> > > here similar to WATERMARK:
> > >
> > > CREATE TABLE output_kafka_t1(
> > >    id bigint,
> > >    msg varchar,
> > >    CHANGE_FLAG FOR isRetraction
> > > ) WITH (
> > >    type=kafka
> > >    ,...
> > > );
> > >
> > > CREATE TABLE output_kafka_t1(
> > >    CHANGE_FLAG FOR isUpsert
> > >    id bigint,
> > >    msg varchar,
> > >    PRIMARY_KEY(id)
> > > ) WITH (
> > >    type=kafka
> > >    ,...
> > > );
> > >
> > > What do you think?
> > >
> > > @Jark: We should definitely stage the discussions and mention the
> > > opinions and advantages/disadvantages that have been proposed already
> in
> > > the FLIP.
> > >
> > > Regards,
> > > Timo
> > >
> > > Am 10.12.18 um 08:10 schrieb Jark Wu:
> > > > Hi all,
> > > >
> > > > It's great to see we have an agreement on MVP.
> > > >
> > > > 4.b) Ingesting and writing timestamps to systems.
> > > > I would treat the field as a physical column not a virtual column. If
> > we
> > > > treat it as computed column, it will be confused that the behavior is
> > > > different when it is a source or sink.
> > > > When it is a physical column, the behavior could be unified. Then the
> > > > problem is how to mapping from the field to kafka message timestamp?
> > > > One is Lin proposed above and is also used in KSQL[1]. Another idea
> is
> > > > introducing a HEADER column which strictly map by name to the fields
> in
> > > > message header.
> > > > For example,
> > > >
> > > > CREATE TABLE output_kafka_t1(
> > > >    id bigint,
> > > >    ts timestamp HEADER,
> > > >    msg varchar
> > > > ) WITH (
> > > >    type=kafka
> > > >    ,...
> > > > );
> > > >
> > > > This is used in Alibaba but not included in the DDL draft. It will
> > > further
> > > > extend the SQL syntax, which is we should be cautious about. What do
> > you
> > > > think about this two solutions?
> > > >
> > > > 4.d) Custom watermark strategies:
> > > > @Timo,  I don't have a strong opinion on this.
> > > >
> > > > 3) SOURCE/SINK/BOTH
> > > > Agree with Lin, GRANT/INVOKE [SELECT|UPDATE] ON TABLE is a clean and
> > > > standard way to manage the permission, which is also adopted by
> HIVE[2]
> > > and
> > > > many databases.
> > > >
> > > > [1]:
> > https://docs.confluent.io/current/ksql/docs/tutorials/examples.html
> > > > [2]:
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=45876173#Hivedeprecatedauthorizationmode/LegacyMode-Grant/RevokePrivileges
> > > >
> > > > @Timo, it's great if someone can conclude the discussion and
> summarize
> > > into
> > > > a FLIP.
> > > > @Shuyi, Thanks a lot for putting it all together. The google doc
> looks
> > > good
> > > > to me, and I left some minor comments there.
> > > >
> > > > Regarding to the FLIP, I have some suggestions:
> > > > 1. The FLIP can contain MILESTONE1 and FUTURE WORKS.
> > > > 2. The MILESTONE1 is the MVP. It describes the MVP DDL syntax.
> > > > 3. Separate FUTURE WORKS into two parts: UNDER DISCUSSION and
> ADOPTED.
> > We
> > > > can derive MILESTONE2 from this easily when it is ready.
> > > >
> > > > I summarized the Future Works based on Shuyi's work:
> > > >
> > > > Adopted: (Should detailed described here...)
> > > > 1. support data type nullability and precision.
> > > > 2. comment on table and columns.
> > > >
> > > > Under Discussion: (Should briefly describe some options...)
> > > > 1. Ingesting and writing timestamps to systems.
> > > > 2. support custom watermark strategy.
> > > > 3. support table update mode
> > > > 4. support row/map/array data type
> > > > 5. support schema derivation
> > > > 6. support system versioned temporal table
> > > > 7. support table index
> > > >
> > > > We can continue the further discussion here, also can separate to an
> > > other
> > > > DISCUSS topic if it is a sophisticated problem such as Table Update
> > Mode,
> > > > Temporal Table.
> > > >
> > > > Best,
> > > > Jark
> > > >
> > > > On Mon, 10 Dec 2018 at 11:54, Lin Li <[hidden email]> wrote:
> > > >
> > > >> hi all,
> > > >> Thanks for your valuable input!
> > > >>
> > > >> 4) Event-Time Attributes and Watermarks:
> > > >> 4.b) @Fabian As you mentioned using a computed columns `ts AS
> > > >> SYSTEMROWTIME()`
> > > >> for writing out to kafka table sink will violate the rule that
> > computed
> > > >> fields are not emitted.
> > > >> Since the timestamp column in kafka's header area is a specific
> > > >> materialization protocol,
> > > >> why don't we treat it as an connector property? For an example:
> > > >> ```
> > > >> CREATE TABLE output_kafka_t1(
> > > >>    id bigint,
> > > >>    ts timestamp,
> > > >>    msg varchar
> > > >> ) WITH (
> > > >>    type=kafka,
> > > >>    header.timestamp=ts
> > > >>    ,...
> > > >> );
> > > >> ```
> > > >>
> > > >> 4d) For custom watermark strategies
> > > >> @Fabian Agree with you that opening another topic about this feature
> > > later.
> > > >>
> > > >> 3) SOURCE / SINK / BOTH
> > > >> I think the permissions and availabilities are two separately
> things,
> > > >> permissions
> > > >> can be managed well by using GRANT/INVOKE(you can call it DCL)
> > solutions
> > > >> which
> > > >> commonly used in different DBs. The permission part can be an new
> > topic
> > > for
> > > >> later discussion, what do you think?
> > > >>
> > > >> For the availabilities, @Fabian @Timo  I've another question,
> > > >> does instantiate a TableSource/Sink cost much or has some other
> > > downsides?
> > > >> IMO, create a new source/sink object via the construct seems not
> > costly.
> > > >> When receiving a DDL we should associate it with the catalog object
> > > >> (reusing an existence or create a new one).
> > > >> Am I lost something important?
> > > >>
> > > >> 5. Schema declaration:
> > > >> @Timo  yes, your concern about the user convenience is very
> important.
> > > But
> > > >> I haven't seen a clear way to solve this so far.
> > > >> Do we put it later and wait for more inputs from the community?
> > > >>
> > > >> Shuyi Chen <[hidden email]> 于2018年12月8日周六 下午4:27写道：
> > > >>
> > > >>> Hi all,
> > > >>>
> > > >>> Thanks a lot for the great discussion. I think we can continue the
> > > >>> discussion here while carving out a MVP so that the community can
> > start
> > > >>> working on. Based on the discussion so far, I try to summarize what
> > we
> > > >> will
> > > >>> do for the MVP:
> > > >>>
> > > >>> MVP
> > > >>>
> > > >>>     1. support CREATE TABLE
> > > >>>     2. support exisiting data type in Flink SQL, ignore nullability
> > and
> > > >>>     precision
> > > >>>     3. support table comments and column comments
> > > >>>     4. support table constraint PRIMARY KEY and UNIQUE
> > > >>>     5. support table properties using key-value pairs
> > > >>>     6. support partitioned by
> > > >>>     7. support computed column
> > > >>>     8. support from-field and from-source timestamp extractors
> > > >>>     9. support PERIODIC-ASCENDING, PERIODIC-BOUNDED, FROM-SOURCE
> > > watermark
> > > >>>     strategies.
> > > >>>     10. support a table property to allow explicit enforcement of
> > > >>>     read/write(source/sink) permission of a table
> > > >>>
> > > >>> I try to put up the DDL grammar (
> > > >>>
> > > >>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit?usp=sharing
> > > >>> )
> > > >>> based on the MVP features above and the previous design docs.
> Please
> > > >> take a
> > > >>> look and comment on it.
> > > >>>
> > > >>>
> > > >>> Also, I summarize the future Improvement on CREATE TABLE as the
> > > >> followings:
> > > >>>     1. support table update mode
> > > >>>     2. support data type nullability and precision
> > > >>>     3. support row/map/array data type
> > > >>>     4. support custom timestamp extractor and watermark strategy
> > > >>>     5. support schema derivation
> > > >>>     6. support system versioned temporal table
> > > >>>     7. support table index
> > > >>>
> > > >>> I suggest we first agree on the MVP feature list and the MVP
> grammar.
> > > And
> > > >>> then we can either continue the discussion of the future
> improvements
> > > >> here,
> > > >>> or create separate JIRAs for each item and discuss further in the
> > JIRA.
> > > >>> What do you guys think?
> > > >>>
> > > >>> Shuyi
> > > >>>
> > > >>> On Fri, Dec 7, 2018 at 7:54 AM Timo Walther <[hidden email]>
> > > wrote:
> > > >>>
> > > >>>> Hi all,
> > > >>>>
> > > >>>> I think we are making good progress. Thanks for all the feedback
> so
> > > >> far.
> > > >>>> 3. Sources/Sinks:
> > > >>>> It seems that I can not find supporters for explicit SOURCE/SINK
> > > >>>> declaration so I'm fine with not using those keywords.
> > > >>>> @Fabian: Maybe we don't haven have to change the TableFactory
> > > interface
> > > >>>> but just provide some helper functions in the TableFactoryService.
> > > This
> > > >>>> would solve the availability problem, but the permission problem
> > would
> > > >>>> still not be solved. If you are fine with it, we could introduce a
> > > >>>> property instead?
> > > >>>>
> > > >>>> 5. Schema declaration:
> > > >>>> @Lin: We should find an agreement on this as it requires changes
> to
> > > the
> > > >>>> TableFactory interface. We should minimize changes to this
> interface
> > > >>>> because it is user-facing. Especially, if format schema and table
> > > >> schema
> > > >>>> differ, the need for such a functionality is very important. Our
> > goal
> > > >> is
> > > >>>> to connect to existing infrastructure. For example, if we are
> using
> > > >> Avro
> > > >>>> and the existing Avro format has enums but Flink SQL does not
> > support
> > > >>>> enums, it would be helpful to let the Avro format derive a table
> > > >> schema.
> > > >>>> Otherwise your need to declare both schemas which leads to CREATE
> > > TABLE
> > > >>>> statements of 400 lines+.
> > > >>>> I think the mentioned query:
> > > >>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>>> format.schema-file = "/my/avrofile.avsc")
> > > >>>> is fine and should only be valid if the schema contains no
> > > non-computed
> > > >>>> columns.
> > > >>>>
> > > >>>> 7. Table Update Mode:
> > > >>>> After thinking about it again, I agree. The mode of the sinks can
> be
> > > >>>> derived from the query and the existence of a PRIMARY KEY
> > declaration.
> > > >>>> But Fabian raised a very good point. How do we deal with sources?
> > > Shall
> > > >>>> we introduce a new keywords similar to WATERMARKS such that a
> > > >>>> upsert/retract flag is not part of the visible schema?
> > > >>>>
> > > >>>> 4a. How to mark a field as attribute?
> > > >>>> @Jark: Thanks for the explanation of the WATERMARK clause
> semantics.
> > > >>>> This is a nice way of marking existing fields. This sounds good to
> > me.
> > > >>>>
> > > >>>> 4c) WATERMARK as constraint
> > > >>>> I'm fine with leaving the WATERMARK clause in the schema
> definition.
> > > >>>>
> > > >>>> 4d) Custom watermark strategies:
> > > >>>> I would already think about custom watermark strategies as the
> > current
> > > >>>> descriptor design already supports this. ScalarFunction's don't
> work
> > > as
> > > >>>> a PeriodicWatermarkAssigner has different semantics. Why not
> simply
> > > >>>> entering the a full class name here as it is done in the current
> > > >> design?
> > > >>>> 4.b) Ingesting and writing timestamps to systems (like Kafka)
> > > >>>> @Fabian: Yes, your suggestion sounds good to me. This behavior
> would
> > > be
> > > >>>> similar to our current `timestamps: from-source` design.
> > > >>>>
> > > >>>> Once our discussion has found a conclusion, I would like to
> > volunteer
> > > >>>> and summarize the outcome of this mailing thread. It nicely aligns
> > > with
> > > >>>> the update work on the connector improvements document (that I
> > wanted
> > > >> to
> > > >>>> do anyway) and the ongoing external catalog discussion.
> > Furthermore, I
> > > >>>> would also want to propose how to change existing interfaces by
> > > keeping
> > > >>>> the DDL, connector improvements, and external catalog support in
> > mind.
> > > >>>> Would that be ok for you?
> > > >>>>
> > > >>>> Thanks,
> > > >>>> Timo
> > > >>>>
> > > >>>>
> > > >>>>
> > > >>>> Am 07.12.18 um 14:48 schrieb Fabian Hueske:
> > > >>>>> Hi all,
> > > >>>>>
> > > >>>>> Thanks for the discussion.
> > > >>>>> I'd like to share my point of view as well.
> > > >>>>>
> > > >>>>> 4) Event-Time Attributes and Watermarks:
> > > >>>>> 4.a) I agree with Lin and Jark's proposal. Declaring a watermark
> on
> > > >> an
> > > >>>>> attribute declares it as an event-time attribute.
> > > >>>>> 4.b) Ingesting and writing timestamps to systems (like Kafka). We
> > > >> could
> > > >>>> use
> > > >>>>> a special function like (ts AS SYSTEMROWTIME()). This function
> will
> > > >>>>> indicate that we read the timestamp directly from the system (and
> > not
> > > >>> the
> > > >>>>> data). We can also write the field back to the system when
> emitting
> > > >> the
> > > >>>>> table (violating the rule that computed fields are not emitted).
> > > >>>>> 4c) I would treat WATERMARK similar to a PRIMARY KEY or UNIQUE
> KEY
> > > >>>>> constraint and therefore keep it in the schema definition.
> > > >>>>> 4d) For custom watermark strategies, a simple expressions or
> > > >>>>> ScalarFunctions won't be sufficient. Sophisticated approaches
> could
> > > >>>> collect
> > > >>>>> histograms, etc. But I think we can leave that out for later.
> > > >>>>>
> > > >>>>> 3) SOURCE / SINK / BOTH
> > > >>>>> As you said, there are two things to consider here: permission
> and
> > > >>>>> availability of a TableSource/TableSink.
> > > >>>>> I think that neither should be a reason to add a keyword at such
> a
> > > >>>>> sensitive position.
> > > >>>>> However, I also see Timo's point that it would be good to know
> > > >> up-front
> > > >>>> how
> > > >>>>> a table can be used without trying to instantiate a
> > TableSource/Sink
> > > >>> for
> > > >>>> a
> > > >>>>> query.
> > > >>>>> Maybe we can extend the TableFactory such that it provides
> > > >> information
> > > >>>>> about which sources/sinks it can provide.
> > > >>>>>
> > > >>>>> 7. Table Update Mode
> > > >>>>> Something that we definitely need to consider is how tables are
> > > >>> ingested,
> > > >>>>> i.e., append, retract or upsert.
> > > >>>>> Especially, since upsert and retraction need a meta-data column
> > that
> > > >>>>> indicates whether an event is an insert (or upsert) or a delete
> > > >> change.
> > > >>>>> This column needs to be identified somehow, most likely as part
> of
> > > >> the
> > > >>>>> input format. Ideally, this column should not be part of the
> table
> > > >>> schema
> > > >>>>> (as it would be always true).
> > > >>>>> Emitting tables is not so much of an issue as the properties of
> the
> > > >>> table
> > > >>>>> tell use what to do (append-only/update, unique key y/n).
> > > >>>>>
> > > >>>>> Best,
> > > >>>>> Fabian
> > > >>>>>
> > > >>>>>
> > > >>>>> Am Fr., 7. Dez. 2018 um 10:39 Uhr schrieb Jark Wu <
> > [hidden email]
> > > >>> :
> > > >>>>>> Hi Timo,
> > > >>>>>>
> > > >>>>>> Thanks for your quickly feedback! Here are some of my thoughts:
> > > >>>>>>
> > > >>>>>> Append, upserts, retract mode on sinks is also a very complex
> > > >>> problem. I
> > > >>>>>> think append/upserts/retract is the ability of a table, user do
> > not
> > > >>>> need to
> > > >>>>>> specify a table is used for append or retraction or upsert. The
> > > >> query
> > > >>>> can
> > > >>>>>> choose which mode the sink is. If an unbounded groupby is
> inserted
> > > >>> into
> > > >>>> an
> > > >>>>>> append sink (the sink only implements/supports append), an
> > exception
> > > >>>> can be
> > > >>>>>> thrown. A more complex problem is, if we want to write
> > > >>>> retractions/upserts
> > > >>>>>> to Kafka, how to encode the change flag (add or retract/delete)
> on
> > > >> the
> > > >>>>>> table? Maybe we should propose some protocal for the change flag
> > > >>>> encoding,
> > > >>>>>> but I don't have a clear idea about this right now.
> > > >>>>>>
> > > >>>>>> 3. Sources/Sinks: The source/sink tag is similar to the
> > > >>>>>> append/upsert/retract problem. Besides source/sink, actully we
> > have
> > > >>>> stream
> > > >>>>>> source, stream sink, batch source, batch sink, and the stream
> sink
> > > >>> also
> > > >>>>>> include append/upsert/retract three modes. Should we put all the
> > > >> tags
> > > >>> on
> > > >>>>>> the CREATE TABLE? IMO, the table's ability is defined by the
> table
> > > >>>> itself,
> > > >>>>>> user do not need to specify it. If it is only a readable table,
> an
> > > >>>>>> exception can be thrown when write to it. As the source/sink tag
> > can
> > > >>> be
> > > >>>>>> omitted in CREATE TABLE, could we skip it and only support
> CREATE
> > > >>> TABLE
> > > >>>> in
> > > >>>>>> the first version, and add it back in the future when we really
> > need
> > > >>>> it? It
> > > >>>>>> keeps API compatible and make sure the MVP is what we consider
> > > >>> clearly.
> > > >>>>>> 4a. How to mark a field as attribute?
> > > >>>>>> The watermark definition includes two parts: use which field as
> > time
> > > >>>>>> attribute and use what generate strategy.
> > > >>>>>> When we want to mark `ts` field as attribute: WATERMARK FOR `ts`
> > AS
> > > >>>> OFFSET
> > > >>>>>> '5' SECOND.
> > > >>>>>> If we have a POJO{id, user, ts} field named "pojo", we can mark
> it
> > > >>> like
> > > >>>>>> this: WATERMARK FOR pojo.ts AS OFFSET '5' SECOND
> > > >>>>>>
> > > >>>>>> 4b. timestamp write to Kafka message header
> > > >>>>>> Even though we can define multiple time attribute on a table,
> only
> > > >> one
> > > >>>> time
> > > >>>>>> attribute can be actived/used in a query (in a stream). When we
> > > >> enable
> > > >>>>>> `writeTiemstamp`, the only attribute actived in the stream will
> be
> > > >>>> write to
> > > >>>>>> Kafka message header. What I mean the timestmap in StreamRecord
> is
> > > >> the
> > > >>>> time
> > > >>>>>> attribute in the stream.
> > > >>>>>>
> > > >>>>>> 4c. Yes. We introduced the WATERMARK keyword similar to the
> INDEX,
> > > >>>> PRIMARY
> > > >>>>>> KEY keywords.
> > > >>>>>>
> > > >>>>>> @Timo, Do you have any other advice or questions on the
> watermark
> > > >>>> syntax ?
> > > >>>>>> For example, the builtin strategy name: "BOUNDED WITH OFFSET" VS
> > > >>>> "OFFSET"
> > > >>>>>> VS ...
> > > >>>>>>
> > > >>>>>>
> > > >>>>>> Cheers,
> > > >>>>>> Jark
> > > >>>>>>
> > > >>>>>> On Fri, 7 Dec 2018 at 17:13, Lin Li <[hidden email]>
> > wrote:
> > > >>>>>>
> > > >>>>>>> Hi Timo,
> > > >>>>>>> Thanks for your feedback, here's some thoughts of mine:
> > > >>>>>>>
> > > >>>>>>> 3. Sources/Sinks:
> > > >>>>>>> "Let's assume an interactive CLI session, people should be able
> > to
> > > >>> list
> > > >>>>>> all
> > > >>>>>>> source table and sink tables to know upfront if they can use an
> > > >>> INSERT
> > > >>>>>> INTO
> > > >>>>>>> here or not."
> > > >>>>>>> This requirement can be simply resolved by a document that list
> > all
> > > >>>>>>> supported source/sink/both connectors and the sql-client can
> > > >> perform
> > > >>> a
> > > >>>>>>> quick check. It's only an implementation choice, not necessary
> > for
> > > >>> the
> > > >>>>>>> syntax.
> > > >>>>>>> For connector implementation, a connector may implement one or
> > some
> > > >>> or
> > > >>>>>> all
> > > >>>>>>> of the [Stream|Batch]Source/[Stream|Batch]Sink traits, we can
> > > >> derive
> > > >>>> the
> > > >>>>>>> availability for any give query without the SOURCE/SINk
> keywords
> > or
> > > >>>>>>> specific table properties in WITH clause.
> > > >>>>>>> Since there's still indeterminacy, shall we skip these two
> > keywords
> > > >>> for
> > > >>>>>> the
> > > >>>>>>> MVP DDL? We can make further discussion after users' feedback.
> > > >>>>>>>
> > > >>>>>>> 6. Partitioning and keys
> > > >>>>>>> Agree with you that raise the priority of table constraint and
> > > >>>>>> partitioned
> > > >>>>>>> table support for better connectivity to Hive and Kafka. I'll
> add
> > > >>>>>>> partitioned table syntax(compatible to hive) into the DDL Draft
> > doc
> > > >>>>>>> later[1].
> > > >>>>>>>
> > > >>>>>>> 5. Schema declaration
> > > >>>>>>> "if users want to declare computed columns they have a "schema"
> > > >>>>>> constraints
> > > >>>>>>> but without columns
> > > >>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>>>>>> format.schema-file = "/my/avrofile.avsc") "
> > > >>>>>>>
> > > >>>>>>>   From the point of my view, this ddl is invalid because the
> > > primary
> > > >>> key
> > > >>>>>>> constraint already references two columns but types unseen.
> > > >>>>>>> And Xuefu pointed a important matching problem, so let's put
> > schema
> > > >>>>>>> derivation as a follow-up extension ?
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>>
> > > >>>>>>> Timo Walther <[hidden email]> 于2018年12月6日周四 下午6:05写道：
> > > >>>>>>>
> > > >>>>>>>> Hi everyone,
> > > >>>>>>>>
> > > >>>>>>>> great to have such a lively discussion. My next batch of
> > feedback:
> > > >>>>>>>>
> > > >>>>>>>> @Jark: We don't need to align the descriptor approach with
> SQL.
> > > >> I'm
> > > >>>>>> open
> > > >>>>>>>> for different approaches as long as we can serve a broad set
> of
> > > >> use
> > > >>>>>>>> cases and systems. The descriptor approach was a first attempt
> > to
> > > >>>> cover
> > > >>>>>>>> all aspects and connector/format characteristics. Just another
> > > >>>> example,
> > > >>>>>>>> that is missing in the DDL design: How can a user decide if
> > > >> append,
> > > >>>>>>>> retraction, or upserts should be used to sink data into the
> > target
> > > >>>>>>>> system? Do we want to define all these improtant properties in
> > the
> > > >>> big
> > > >>>>>>>> WITH property map? If yes, we are already close to the
> > descriptor
> > > >>>>>>>> approach. Regarding the "standard way", most DDL languages
> have
> > > >> very
> > > >>>>>>>> custom syntax so there is not a real "standard".
> > > >>>>>>>>
> > > >>>>>>>> 3. Sources/Sinks: @Lin: If a table has both read/write access
> it
> > > >> can
> > > >>>> be
> > > >>>>>>>> created using a regular CREATE TABLE (omitting a specific
> > > >>> source/sink)
> > > >>>>>>>> declaration. Regarding the transition from source/sink to
> both,
> > > >> yes
> > > >>> we
> > > >>>>>>>> would need to update the a DDL and catalogs. But is this a
> > > >> problem?
> > > >>>> One
> > > >>>>>>>> also needs to add new queries that use the tables. @Xuefu: It
> is
> > > >> not
> > > >>>>>>>> only about security aspects. Especially for streaming use
> cases,
> > > >> not
> > > >>>>>>>> every connector can be used as a source easily. For example, a
> > > >> JDBC
> > > >>>>>> sink
> > > >>>>>>>> is easier than a JDBC source. Let's assume an interactive CLI
> > > >>> session,
> > > >>>>>>>> people should be able to list all source table and sink tables
> > to
> > > >>> know
> > > >>>>>>>> upfront if they can use an INSERT INTO here or not.
> > > >>>>>>>>
> > > >>>>>>>> 6. Partitioning and keys: @Lin: I would like to include this
> in
> > > >> the
> > > >>>>>>>> design given that Hive integration and Kafka key support are
> in
> > > >> the
> > > >>>>>>>> making/are on our roadmap for this release.
> > > >>>>>>>>
> > > >>>>>>>> 5. Schema declaration: @Lin: You are right it is not
> > conflicting.
> > > >> I
> > > >>>>>> just
> > > >>>>>>>> wanted to raise the point because if users want to declare
> > > >> computed
> > > >>>>>>>> columns they have a "schema" constraints but without columns.
> > Are
> > > >> we
> > > >>>> ok
> > > >>>>>>>> with a syntax like ...
> > > >>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> > > >>>>>>>> format.schema-file = "/my/avrofile.avsc") ?
> > > >>>>>>>> @Xuefu: Yes, you are right that an external schema might not
> > > >> excatly
> > > >>>>>>>> match but this is true for both directions:
> > > >>>>>>>> table schema "derives" format schema and format schema
> "derives"
> > > >>> table
> > > >>>>>>>> schema.
> > > >>>>>>>>
> > > >>>>>>>> 7. Hive compatibility: @Xuefu: I agree that Hive is popular
> but
> > we
> > > >>>>>>>> should not just adopt everything from Hive as there syntax is
> > very
> > > >>>>>>>> batch-specific. We should come up with a superset of
> historical
> > > >> and
> > > >>>>>>>> future requirements. Supporting Hive queries can be an
> > > >> intermediate
> > > >>>>>>>> layer on top of Flink's DDL.
> > > >>>>>>>>
> > > >>>>>>>> 4. Time attributes: @Lin: I'm fine with changing the
> > > >>>> TimestampExtractor
> > > >>>>>>>> interface as this is also important for better separation of
> > > >>> connector
> > > >>>>>>>> and table module [1]. However, I'm wondering about watermark
> > > >>>>>> generation.
> > > >>>>>>>> 4a. timestamps are in the schema twice:
> > > >>>>>>>> @Jark: "existing field is Long/Timestamp, we can just use it
> as
> > > >>>>>>>> rowtime": yes, but we need to mark a field as such an
> attribute.
> > > >> How
> > > >>>>>>>> does the syntax for marking look like? Also in case of
> > timestamps
> > > >>> that
> > > >>>>>>>> are nested in the schema?
> > > >>>>>>>>
> > > >>>>>>>> 4b. how can we write out a timestamp into the message header?:
> > > >>>>>>>> I agree to simply ignore computed columns when writing out.
> This
> > > >> is
> > > >>>>>> like
> > > >>>>>>>> 'field-change: add' that I mentioned in the improvements
> > document.
> > > >>>>>>>> @Jark: "then the timestmap in StreamRecord will be write to
> > Kafka
> > > >>>>>>>> message header": Unfortunately, there is no timestamp in the
> > > >> stream
> > > >>>>>>>> record. Additionally, multiple time attributes can be in a
> > schema.
> > > >>> So
> > > >>>>>> we
> > > >>>>>>>> need a constraint that tells the sink which column to use
> > > >> (possibly
> > > >>>>>>>> computed as well)?
> > > >>>>>>>>
> > > >>>>>>>> 4c. separate all time attribute concerns into a special clause
> > > >> next
> > > >>> to
> > > >>>>>>>> the regular schema?
> > > >>>>>>>> @Jark: I don't have a strong opinion on this. I just have the
> > > >>> feeling
> > > >>>>>>>> that the "schema part" becomes quite messy because the actual
> > > >> schema
> > > >>>>>>>> with types and fields is accompanied by so much metadata about
> > > >>>>>>>> timestamps, watermarks, keys,... and we would need to
> introduce
> > a
> > > >>> new
> > > >>>>>>>> WATERMARK keyword within a schema that was close to standard
> up
> > to
> > > >>>> this
> > > >>>>>>>> point.
> > > >>>>>>>>
> > > >>>>>>>> Thanks everyone,
> > > >>>>>>>> Timo
> > > >>>>>>>>
> > > >>>>>>>> [1] https://issues.apache.org/jira/browse/FLINK-9461
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>>
> > > >>>>>>>> Am 06.12.18 um 07:08 schrieb Jark Wu:
> > > >>>>>>>>> Hi Timo,
> > > >>>>>>>>>
> > > >>>>>>>>> Thank you for the valuable feedbacks.
> > > >>>>>>>>>
> > > >>>>>>>>> First of all, I think we don't need to align the SQL
> > > >> functionality
> > > >>> to
> > > >>>>>>>>> Descriptor. Because SQL is a more standard API, we should be
> as
> > > >>>>>>> cautious
> > > >>>>>>>> as
> > > >>>>>>>>> possible to extend the SQL syntax. If something can be done
> in
> > a
> > > >>>>>>> standard
> > > >>>>>>>>> way, we shouldn't introduce something new.
> > > >>>>>>>>>
> > > >>>>>>>>> Here are some of my thoughts:
> > > >>>>>>>>>
> > > >>>>>>>>> 1. Scope: Agree.
> > > >>>>>>>>> 2. Constraints: Agree.
> > > >>>>>>>>> 4. Time attributes:
> > > >>>>>>>>>      4a. timestamps are in the schema twice.
> > > >>>>>>>>>       If an existing field is Long/Timestamp, we can just use
> > it
> > > >> as
> > > >>>>>>>> rowtime,
> > > >>>>>>>>> no twice defined. If it is not a Long/Timestamp, we use
> > computed
> > > >>>>>> column
> > > >>>>>>>> to
> > > >>>>>>>>> get an expected timestamp column to be rowtime, is this what
> > you
> > > >>> mean
> > > >>>>>>>>> defined twice?  But I don't think it is a problem, but an
> > > >>> advantages,
> > > >>>>>>>>> because it is easy to use, user do not need to consider
> whether
> > > >> to
> > > >>>>>>>> "replace
> > > >>>>>>>>> the existing column" or "add a new column", he will not be
> > > >> confused
> > > >>>>>>>> what's
> > > >>>>>>>>> the real schema is, what's the index of rowtime in the
> schema?
> > > >>>>>>> Regarding
> > > >>>>>>>> to
> > > >>>>>>>>> the optimization, even if timestamps are in schema twice,
> when
> > > >> the
> > > >>>>>>>> original
> > > >>>>>>>>> timestamp is never used in query, then the projection
> pushdown
> > > >>>>>>>> optimization
> > > >>>>>>>>> can cut this field as early as possible, which is exactly the
> > > >> same
> > > >>> as
> > > >>>>>>>>> "replacing the existing column" in runtime.
> > > >>>>>>>>>
> > > >>>>>>>>>       4b. how can we write out a timestamp into the message
> > > >> header?
> > > >>>>>>>>>        That's a good point. I think computed column is just a
> > > >>> virtual
> > > >>>>>>>> column
> > > >>>>>>>>> on table which is only relative to reading. If we want to
> write
> > > >> to
> > > >>> a
> > > >>>>>>>> table
> > > >>>>>>>>> with computed column defined, we only need to provide the
> > columns
> > > >>>>>>> except
> > > >>>>>>>>> computed columns (see SQL Server [1]). The computed column is
> > > >>> ignored
> > > >>>>>>> in
> > > >>>>>>>>> the insert statement. Get back to the question, how can we
> > write
> > > >>> out
> > > >>>>>> a
> > > >>>>>>>>> timestamp into the message header? IMO, we can provide a
> > > >>>>>> configuration
> > > >>>>>>> to
> > > >>>>>>>>> support this, such as `kafka.writeTimestamp=true`, then the
> > > >>> timestmap
> > > >>>>>>> in
> > > >>>>>>>>> StreamRecord will be write to Kafka message header. What do
> you
> > > >>>>>> think?
> > > >>>>>>>>>        4c. separate all time attribute concerns into a
> special
> > > >>> clause
> > > >>>>>>> next
> > > >>>>>>>> to
> > > >>>>>>>>> the regular schema?
> > > >>>>>>>>>        Separating watermark into a special clause similar to
> > > >>>>>> PARTITIONED
> > > >>>>>>>> BY is
> > > >>>>>>>>> also a good idea. Conceptually, it's fine to put watermark in
> > > >>> schema
> > > >>>>>>> part
> > > >>>>>>>>> or out schema part. But if we want to support multiple
> > watermark
> > > >>>>>>>>> definition, maybe it would be better to put it in schema
> part.
> > It
> > > >>> is
> > > >>>>>>>>> similar to Index Definition that we can define several
> indexes
> > > >> on a
> > > >>>>>>> table
> > > >>>>>>>>> in schema part.
> > > >>>>>>>>>
> > > >>>>>>>>>        4d. How can people come up with a custom watermark
> > > >> strategy?
> > > >>>>>>>>>        In most cases, the built-in strategy can works good.
> If
> > we
> > > >>> need
> > > >>>>>> a
> > > >>>>>>>>> custom one, we can use a scalar function which restrict to
> only
> > > >>>>>> return
> > > >>>>>>> a
> > > >>>>>>>>> nullable Long, and use it in SQL like: WATERMARK for rowtime
> AS
> > > >>>>>>>>> watermarkUdf(a, b, c). The `watermarkUdf` is a user-defined
> > > >> scalar
> > > >>>>>>>> function
> > > >>>>>>>>> accepts 3 parameters and return a nullable Long which can be
> > used
> > > >>> as
> > > >>>>>>>>> punctuated watermark assigner. Another choice is
> implementing a
> > > >>> class
> > > >>>>>>>>> extending the
> > > >>>>>>>>>
> `org.apache.flink.table.sources.wmstrategies.WatermarkStrategy`
> > > >> and
> > > >>>>>> use
> > > >>>>>>>> it
> > > >>>>>>>>> in SQL: WATERMARK for rowtime AS
> 'com.my.MyWatermarkStrategy'.
> > > >> But
> > > >>> if
> > > >>>>>>>>> scalar function can cover the requirements here, I would
> prefer
> > > >> it
> > > >>>>>>> here,
> > > >>>>>>>>> because it keeps standard compliant. BTW, this feature is not
> > in
> > > >>> MVP,
> > > >>>>>>> we
> > > >>>>>>>>> can discuss it more depth in the future when we need it.
> > > >>>>>>>>>
> > > >>>>>>>>> 5. Schema declaration:
> > > >>>>>>>>> I like the proposal to omit the schema if we can get the
> schema
> > > >>> from
> > > >>>>>>>>> external storage or something schema file. Actually, we have
> > > >>> already
> > > >>>>>>>>> encountered this requirement in out company.
> > > >>>>>>>>>
> > > >>>>>>>>>
> > > >>>>>>>>> +1 to @Xuefu that we should be as close as possible to Hive
> > > >> syntax
> > > >>>>>>> while
> > > >>>>>>>>> keeping SQL ANSI standard. This will make it more acceptable
> > and
> > > >>>>>> reduce
> > > >>>>>>>> the
> > > >>>>>>>>> learning cost for user.
> > > >>>>>>>>>
> > > >>>>>>>>> [1]:
> > > >>>>>>>>>
> > > >>
> > >
> >
> https://docs.microsoft.com/en-us/sql/relational-databases/partitions/create-partitioned-tables-and-indexes?view=sql-server-2017
> > > >>>>>>>>> Best,
> > > >>>>>>>>> Jark
> > > >>>>>>>>>
> > > >>>>>>>>> On Thu, 6 Dec 2018 at 12:09, Zhang, Xuefu <
> > > >> [hidden email]
> > > >>>>>>>> wrote:
> > > >>>>>>>>>> Hi Timo/Shuyi/Lin,
> > > >>>>>>>>>>
> > > >>>>>>>>>> Thanks for the discussions. It seems that we are converging
> to
> > > >>>>>>> something
> > > >>>>>>>>>> meaningful. Here are some of my thoughts:
> > > >>>>>>>>>>
> > > >>>>>>>>>> 1. +1 on MVP DDL
> > > >>>>>>>>>> 3. Markers for source or sink seem more about permissions on
> > > >>> tables
> > > >>>>>>> that
> > > >>>>>>>>>> belong to a security component. Unless the table is created
> > > >>>>>>> differently
> > > >>>>>>>>>> based on source, sink, or both, it doesn't seem necessary to
> > use
> > > >>>>>> these
> > > >>>>>>>>>> keywords to enforce permissions.
> > > >>>>>>>>>> 5. It might be okay if schema declaration is always needed.
> > > >> While
> > > >>>>>>> there
> > > >>>>>>>>>> might be some duplication sometimes, it's not always true.
> For
> > > >>>>>>> example,
> > > >>>>>>>>>> external schema may not be exactly matching Flink schema.
> For
> > > >>>>>>> instance,
> > > >>>>>>>>>> data types. Even if so, perfect match is not required. For
> > > >>> instance,
> > > >>>>>>> the
> > > >>>>>>>>>> external schema file may evolve while table schema in Flink
> > may
> > > >>> stay
> > > >>>>>>>>>> unchanged. A responsible reader should be able to scan the
> > file
> > > >>>>>> based
> > > >>>>>>> on
> > > >>>>>>>>>> file schema and return the data based on table schema.
> > > >>>>>>>>>>
> > > >>>>>>>>>> Other aspects:
> > > >>>>>>>>>>
> > > >>>>>>>>>> 7. Hive compatibility. Since Flink SQL will soon be able to
> > > >>> operate
> > > >>>>>> on
> > > >>>>>>>>>> Hive metadata and data, it's an add-on benefit if we can be
> > > >>>>>> compatible
> > > >>>>>>>> with
> > > >>>>>>>>>> Hive syntax/semantics while following ANSI standard. At
> least
> > we
> > > >>>>>>> should
> > > >>>>>>>> be
> > > >>>>>>>>>> as close as possible. Hive DDL can found at
> > > >>>>>>>>>>
> > > >>>
> https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL
> > > >>>>>>>>>> Thanks,
> > > >>>>>>>>>> Xuefu
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >> ------------------------------------------------------------------
> > > >>>>>>>>>> Sender:Lin Li <[hidden email]>
> > > >>>>>>>>>> Sent at:2018 Dec 6 (Thu) 10:49
> > > >>>>>>>>>> Recipient:dev <[hidden email]>
> > > >>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> > > >>>>>>>>>>
> > > >>>>>>>>>> Hi Timo and Shuyi,
> > > >>>>>>>>>>      thanks for your feedback.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 1. Scope
> > > >>>>>>>>>> agree with you we should focus on the MVP DDL first.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 2. Constraints
> > > >>>>>>>>>> yes, this can be a follow-up issue.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 3. Sources/Sinks
> > > >>>>>>>>>> If a TABLE has both read/write access requirements, should
> we
> > > >>>>>> declare
> > > >>>>>>> it
> > > >>>>>>>>>> using
> > > >>>>>>>>>> `CREATE [SOURCE_SINK|BOTH] TABLE tableName ...` ? A further
> > > >>>>>> question,
> > > >>>>>>>> if a
> > > >>>>>>>>>> TABLE
> > > >>>>>>>>>> t1 firstly declared as read only (as a source table), then
> for
> > > >>> some
> > > >>>>>>> new
> > > >>>>>>>>>> requirements
> > > >>>>>>>>>> t1 will change to a sink table,  in this case we need
> updating
> > > >>> both
> > > >>>>>>> the
> > > >>>>>>>> DDL
> > > >>>>>>>>>> and catalogs.
> > > >>>>>>>>>> Further more, let's think about the BATCH query, update one
> > > >> table
> > > >>>>>>>> in-place
> > > >>>>>>>>>> can be a common case.
> > > >>>>>>>>>> e.g.,
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> CREATE TABLE t1 (
> > > >>>>>>>>>>      col1 varchar,
> > > >>>>>>>>>>      col2 int,
> > > >>>>>>>>>>      col3 varchar
> > > >>>>>>>>>>      ...
> > > >>>>>>>>>> );
> > > >>>>>>>>>>
> > > >>>>>>>>>> INSERT [OVERWRITE] TABLE t1
> > > >>>>>>>>>> AS
> > > >>>>>>>>>> SELECT
> > > >>>>>>>>>>      (some computing ...)
> > > >>>>>>>>>> FROM t1;
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> So, let's forget these SOURCE/SINK keywords in DDL. For the
> > > >>>>>> validation
> > > >>>>>>>>>> purpose, we can find out other ways.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 4. Time attributes
> > > >>>>>>>>>> As Shuyi mentioned before, there exists an
> > > >>>>>>>>>>
> > `org.apache.flink.table.sources.tsextractors.TimestampExtractor`
> > > >>> for
> > > >>>>>>>> custom
> > > >>>>>>>>>> defined time attributes usage, but this expression based
> class
> > > >> is
> > > >>>>>> more
> > > >>>>>>>>>> friendly for table api not the SQL.
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> /**
> > > >>>>>>>>>>      * Provides the an expression to extract the timestamp
> > for a
> > > >>>>>> rowtime
> > > >>>>>>>>>> attribute.
> > > >>>>>>>>>>      */
> > > >>>>>>>>>> abstract class TimestampExtractor extends
> FieldComputer[Long]
> > > >> with
> > > >>>>>>>>>> Serializable {
> > > >>>>>>>>>>
> > > >>>>>>>>>>      /** Timestamp extractors compute the timestamp as Long.
> > */
> > > >>>>>>>>>>      override def getReturnType: TypeInformation[Long] =
> > > >>>>>>>>>> Types.LONG.asInstanceOf[TypeInformation[Long]]
> > > >>>>>>>>>> }
> > > >>>>>>>>>> ```
> > > >>>>>>>>>> BTW, I think both the Scalar function and the
> > TimestampExtractor
> > > >>> are
> > > >>>>>>>>>> expressing computing logic, the TimestampExtractor has no
> more
> > > >>>>>>>> advantage in
> > > >>>>>>>>>> SQL scenarios.
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>> 6. Partitioning and keys
> > > >>>>>>>>>> Primary Key is included in Constraint part, and partitioned
> > > >> table
> > > >>>>>>>> support
> > > >>>>>>>>>> can be another topic later.
> > > >>>>>>>>>>
> > > >>>>>>>>>> 5. Schema declaration
> > > >>>>>>>>>> Agree with you that we can do better schema derivation for
> > user
> > > >>>>>>>>>> convenience, but this is not conflict with the syntax.
> > > >>>>>>>>>> Table properties can carry any useful informations both for
> > the
> > > >>>>>> users
> > > >>>>>>>> and
> > > >>>>>>>>>> the framework, I like your `contract name` proposal,
> > > >>>>>>>>>> e.g., `WITH (format.type = avro)`, the framework can
> recognize
> > > >>> some
> > > >>>>>>>>>> `contract name` like `format.type`, `connector.type` and
> etc.
> > > >>>>>>>>>> And also derive the table schema from an existing schema
> file
> > > >> can
> > > >>> be
> > > >>>>>>>> handy
> > > >>>>>>>>>> especially one with too many table columns.
> > > >>>>>>>>>>
> > > >>>>>>>>>> Regards,
> > > >>>>>>>>>> Lin
> > > >>>>>>>>>>
> > > >>>>>>>>>>
> > > >>>>>>>>>> Timo Walther <[hidden email]> 于2018年12月5日周三 下午10:40写道：
> > > >>>>>>>>>>
> > > >>>>>>>>>>> Hi Jark and Shuyi,
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> thanks for pushing the DDL efforts forward. I agree that we
> > > >>> should
> > > >>>>>>> aim
> > > >>>>>>>>>>> to combine both Shuyi's design and your design.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> Here are a couple of concerns that I think we should
> address
> > in
> > > >>> the
> > > >>>>>>>>>> design:
> > > >>>>>>>>>>> 1. Scope: Let's focuses on a MVP DDL for CREATE TABLE
> > > >> statements
> > > >>>>>>> first.
> > > >>>>>>>>>>> I think this topic has already enough potential for long
> > > >>>>>> discussions
> > > >>>>>>>> and
> > > >>>>>>>>>>> is very helpful for users. We can discuss CREATE VIEW and
> > > >> CREATE
> > > >>>>>>>>>>> FUNCTION afterwards as they are not related to each other.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 2. Constraints: I think we should consider things like
> > > >>> nullability,
> > > >>>>>>>>>>> VARCHAR length, and decimal scale and precision in the
> future
> > > >> as
> > > >>>>>> they
> > > >>>>>>>>>>> allow for nice optimizations. However, since both the
> > > >> translation
> > > >>>>>> and
> > > >>>>>>>>>>> runtime operators do not support those features. I would
> not
> > > >>>>>>> introduce
> > > >>>>>>>> a
> > > >>>>>>>>>>> arbitrary default value but omit those parameters for now.
> > This
> > > >>> can
> > > >>>>>>> be
> > > >>>>>>>> a
> > > >>>>>>>>>>> follow-up issue once the basic DDL has been merged.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 3. Sources/Sinks: We had a discussion about CREATE TABLE vs
> > > >>> CREATE
> > > >>>>>>>>>>> [SOURCE|SINK|] TABLE before. In my opinion we should allow
> > for
> > > >>>>>> these
> > > >>>>>>>>>>> explicit declaration because in most production scenarios,
> > > >> teams
> > > >>>>>> have
> > > >>>>>>>>>>> strict read/write access requirements. For example, a data
> > > >>> science
> > > >>>>>>> team
> > > >>>>>>>>>>> should only consume from a event Kafka topic but should not
> > > >>>>>>> accidently
> > > >>>>>>>>>>> write back to the single source of truth.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 4. Time attributes: In general, I like your computed
> columns
> > > >>>>>> approach
> > > >>>>>>>>>>> because it makes defining a rowtime attributes transparent
> > and
> > > >>>>>>> simple.
> > > >>>>>>>>>>> However, there are downsides that we should discuss.
> > > >>>>>>>>>>> 4a. Jarks current design means that timestamps are in the
> > > >> schema
> > > >>>>>>> twice.
> > > >>>>>>>>>>> The design that is mentioned in [1] makes this more
> flexible
> > as
> > > >>> it
> > > >>>>>>>>>>> either allows to replace an existing column or add a
> computed
> > > >>>>>> column.
> > > >>>>>>>>>>> 4b. We need to consider the zoo of storage systems that is
> > out
> > > >>>>>> there
> > > >>>>>>>>>>> right now. Take Kafka as an example, how can we write out a
> > > >>>>>> timestamp
> > > >>>>>>>>>>> into the message header? We need to think of a reverse
> > > >> operation
> > > >>>>>> to a
> > > >>>>>>>>>>> computed column.
> > > >>>>>>>>>>> 4c. Does defining a watermark really fit into the schema
> part
> > > >> of
> > > >>> a
> > > >>>>>>>>>>> table? Shouldn't we separate all time attribute concerns
> > into a
> > > >>>>>>> special
> > > >>>>>>>>>>> clause next to the regular schema, similar how PARTITIONED
> BY
> > > >>> does
> > > >>>>>> it
> > > >>>>>>>> in
> > > >>>>>>>>>>> Hive?
> > > >>>>>>>>>>> 4d. How can people come up with a custom watermark
> strategy?
> > I
> > > >>>>>> guess
> > > >>>>>>>>>>> this can not be implemented in a scalar function and would
> > > >>> require
> > > >>>>>>> some
> > > >>>>>>>>>>> new type of UDF?
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 6. Partitioning and keys: Another question that the DDL
> > design
> > > >>>>>> should
> > > >>>>>>>>>>> answer is how do we express primary keys (for upserts),
> > > >>>>>> partitioning
> > > >>>>>>>>>>> keys (for Hive, Kafka message keys). All part of the table
> > > >>> schema?
> > > >>>>>>>>>>> 5. Schema declaration: I find it very annoying that we want
> > to
> > > >>>>>> force
> > > >>>>>>>>>>> people to declare all columns and types again even though
> > this
> > > >> is
> > > >>>>>>>>>>> usually already defined in some company-wide format. I know
> > > >> that
> > > >>>>>>>> catalog
> > > >>>>>>>>>>> support will greatly improve this. But if no catalog is
> used,
> > > >>>>>> people
> > > >>>>>>>>>>> need to manually define a schema with 50+ fields in a Flink
> > > >> DDL.
> > > >>>>>>> What I
> > > >>>>>>>>>>> actually promoted having two ways of reading data:
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 1. Either the format derives its schema from the table
> > schema.
> > > >>>>>>>>>>> CREATE TABLE (col INT) WITH (format.type = avro)
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> 2. Or the table schema can be omitted and the format schema
> > > >>> defines
> > > >>>>>>> the
> > > >>>>>>>>>>> table schema (+ time attributes).
> > > >>>>>>>>>>> CREATE TABLE WITH (format.type = avro, format.schema-file =
> > > >>>>>>>>>>> "/my/avrofile.avsc")
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> Please let me know what you think about each item. I will
> try
> > > >> to
> > > >>>>>>>>>>> incorporate your feedback in [1] this week.
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> Regards,
> > > >>>>>>>>>>> Timo
> > > >>>>>>>>>>>
> > > >>>>>>>>>>> [1]
> > > >>>>>>>>>>>
> > > >>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit#heading=h.41fd6rs7b3cf
> > > >>>>>>>>>>> Am 05.12.18 um 13:01 schrieb Jark Wu:
> > > >>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> It's exciting to see we can make such a great progress
> here.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> Regarding to the watermark:
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> Watermarks can be defined on any columns (including
> > > >>>>>> computed-column)
> > > >>>>>>>> in
> > > >>>>>>>>>>>> table schema.
> > > >>>>>>>>>>>> The computed column can be computed from existing columns
> > > >> using
> > > >>>>>>>> builtin
> > > >>>>>>>>>>>> functions and *UserDefinedFunctions* (ScalarFunction).
> > > >>>>>>>>>>>> So IMO, it can work out for almost all the scenarios not
> > only
> > > >>>>>> common
> > > >>>>>>>>>>>> scenarios.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> I don't think using a `TimestampExtractor` to support
> custom
> > > >>>>>>> timestamp
> > > >>>>>>>>>>>> extractor in SQL is a good idea. Because
> > `TimestampExtractor`
> > > >>>>>>>>>>>> is not a SQL standard function. If we support
> > > >>> `TimestampExtractor`
> > > >>>>>>> in
> > > >>>>>>>>>>> SQL,
> > > >>>>>>>>>>>> do we need to support CREATE FUNCTION for
> > > >> `TimestampExtractor`?
> > > >>>>>>>>>>>> I think `ScalarFunction` can do the same thing with
> > > >>>>>>>>>> `TimestampExtractor`
> > > >>>>>>>>>>>> but more powerful and standard.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> The core idea of the watermark definition syntax is that
> the
> > > >>>>>> schema
> > > >>>>>>>>>> part
> > > >>>>>>>>>>>> defines all the columns of the table, it is exactly what
> the
> > > >>> query
> > > >>>>>>>>>> sees.
> > > >>>>>>>>>>>> The watermark part is something like a primary key
> > definition
> > > >> or
> > > >>>>>>>>>>> constraint
> > > >>>>>>>>>>>> on SQL Table, it has no side effect on the schema, only
> > > >> defines
> > > >>>>>> what
> > > >>>>>>>>>>>> watermark strategy is and makes which field as the rowtime
> > > >>>>>> attribute
> > > >>>>>>>>>>> field.
> > > >>>>>>>>>>>> If the rowtime field is not in the existing fields, we can
> > use
> > > >>>>>>>> computed
> > > >>>>>>>>>>>> column
> > > >>>>>>>>>>>> to generate it from other existing fields. The Descriptor
> > > >>> Pattern
> > > >>>>>>> API
> > > >>>>>>>>>> [1]
> > > >>>>>>>>>>>> is very useful when writing a Table API job, but is not
> > > >>>>>>> contradictory
> > > >>>>>>>>>> to
> > > >>>>>>>>>>>> the
> > > >>>>>>>>>>>> Watermark DDL from my perspective.
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> [1]:
> > > >>>>>>>>>>>>
> > > >>
> > >
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > > >>>>>>>>>>>> .
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> Best,
> > > >>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>
> > > >>>>>>>>>>>> On Wed, 5 Dec 2018 at 17:58, Shuyi Chen <
> [hidden email]
> > >
> > > >>>>>> wrote:
> > > >>>>>>>>>>>>> Hi Jark and Shaoxuan,
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> Thanks a lot for the summary. I think we are making great
> > > >>>>>> progress
> > > >>>>>>>>>> here.
> > > >>>>>>>>>>>>> Below are my thoughts.
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> *(1) watermark definition
> > > >>>>>>>>>>>>> IMO, it's better to keep it consistent with the rowtime
> > > >>>>>> extractors
> > > >>>>>>>> and
> > > >>>>>>>>>>>>> watermark strategies defined in
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>>
> > > >>
> > >
> >
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> > > >>>>>>>>>>>>> .
> > > >>>>>>>>>>>>> Using built-in functions seems to be too much for most of
> > the
> > > >>>>>>> common
> > > >>>>>>>>>>>>> scenarios.
> > > >>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > > >>>>>>>>>>>>> Actually, I think we can put the source/sink type info
> into
> > > >> the
> > > >>>>>>> table
> > > >>>>>>>>>>>>> properties, so we can use CREATE TABLE.
> > > >>>>>>>>>>>>> (3) View DDL with properties
> > > >>>>>>>>>>>>> We can remove the view properties section now for the MVP
> > and
> > > >>> add
> > > >>>>>>> it
> > > >>>>>>>>>>> back
> > > >>>>>>>>>>>>> later if needed.
> > > >>>>>>>>>>>>> (4) Type Definition
> > > >>>>>>>>>>>>> I agree we can put the type length or precision into
> future
> > > >>>>>>> versions.
> > > >>>>>>>>>> As
> > > >>>>>>>>>>>>> for the grammar difference, currently, I am using the
> > grammar
> > > >>> in
> > > >>>>>>>>>> Calcite
> > > >>>>>>>>>>>>> type DDL, but since we'll extend the parser in Flink, so
> we
> > > >> can
> > > >>>>>>>>>>> definitely
> > > >>>>>>>>>>>>> change if needed.
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>
> > > >>>>>>>>>>>>> On Tue, Dec 4, 2018 at 10:48 PM Jark Wu <
> [hidden email]>
> > > >>>>>> wrote:
> > > >>>>>>>>>>>>>> Hi Shaoxuan,
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> Thanks for pointing that out. Yes, the source/sink tag
> on
> > > >>> create
> > > >>>>>>>>>> table
> > > >>>>>>>>>>> is
> > > >>>>>>>>>>>>>> the another major difference.
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> Summarize the main differences again:
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> *(1) watermark definition
> > > >>>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> > > >>>>>>>>>>>>>> (3) View DDL with properties
> > > >>>>>>>>>>>>>> (4) Type Definition
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> Best,
> > > >>>>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>> On Wed, 5 Dec 2018 at 14:08, Shaoxuan Wang <
> > > >>> [hidden email]
> > > >>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>> Hi Jark,
> > > >>>>>>>>>>>>>>> Thanks for the summary. Your plan for the 1st round
> > > >>>>>>> implementation
> > > >>>>>>>>>> of
> > > >>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>> looks good to me.
> > > >>>>>>>>>>>>>>> Have we reached the agreement on simplifying/unifying
> > > >> "create
> > > >>>>>>>>>>>>>> [source/sink]
> > > >>>>>>>>>>>>>>> table" to "create table"? "Watermark definition" and
> > > >> "create
> > > >>>>>>> table"
> > > >>>>>>>>>>> are
> > > >>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>> major obstacles on the way to merge two design
> proposals
> > > >>> FMPOV.
> > > >>>>>>>>>>> @Shuyi,
> > > >>>>>>>>>>>>>> It
> > > >>>>>>>>>>>>>>> would be great if you can spend time and respond to
> these
> > > >> two
> > > >>>>>>> parts
> > > >>>>>>>>>>>>>> first.
> > > >>>>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>>>> Shaoxuan
> > > >>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>> On Wed, Dec 5, 2018 at 12:20 PM Jark Wu <
> > [hidden email]>
> > > >>>>>>> wrote:
> > > >>>>>>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> It seems that you have reviewed the DDL doc [1] that
> Lin
> > > >>> and I
> > > >>>>>>>>>>>>> drafted.
> > > >>>>>>>>>>>>>>>> This doc covers all the features running in Alibaba.
> > > >>>>>>>>>>>>>>>> But some of features might be not needed in the first
> > > >>> version
> > > >>>>>> of
> > > >>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>> SQL
> > > >>>>>>>>>>>>>>>> DDL.
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> So my suggestion would be to focus on the MVP DDLs and
> > > >> reach
> > > >>>>>>>>>>>>> agreement
> > > >>>>>>>>>>>>>>> ASAP
> > > >>>>>>>>>>>>>>>> based on the DDL draft [1] and the DDL design [2]
> Shuyi
> > > >>>>>>> proposed.
> > > >>>>>>>>>>>>>>>> And we can discuss on the main differences one by one.
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> The following is the MVP DDLs should be included in
> the
> > > >>> first
> > > >>>>>>>>>> version
> > > >>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>> my
> > > >>>>>>>>>>>>>>>> opinion (feedbacks are welcome):
> > > >>>>>>>>>>>>>>>> (1) Table DDL:
> > > >>>>>>>>>>>>>>>>         (1.1) Type definition
> > > >>>>>>>>>>>>>>>>         (1.2) computed column definition
> > > >>>>>>>>>>>>>>>>         (1.3) watermark definition
> > > >>>>>>>>>>>>>>>>         (1.4) with properties
> > > >>>>>>>>>>>>>>>>         (1.5) table constraint (primary key/unique)
> > > >>>>>>>>>>>>>>>>         (1.6) column nullability (nice to have)
> > > >>>>>>>>>>>>>>>> (2) View DDL
> > > >>>>>>>>>>>>>>>> (3) Function DDL
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> The main differences from two DDL docs (sth maybe
> > missed,
> > > >>>>>>> welcome
> > > >>>>>>>>>> to
> > > >>>>>>>>>>>>>>> point
> > > >>>>>>>>>>>>>>>> out):
> > > >>>>>>>>>>>>>>>> *(1.3) watermark*: this is the main and the most
> > important
> > > >>>>>>>>>>>>> difference,
> > > >>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>> would be great if @Timo Walther <[hidden email]>
> > > >>> @Fabian
> > > >>>>>>>>>> Hueske
> > > >>>>>>>>>>>>>>>> <[hidden email]>  give some feedbacks.
> > > >>>>>>>>>>>>>>>>      (1.1) Type definition:
> > > >>>>>>>>>>>>>>>>           (a) Should VARCHAR carry a length, e.g.
> > > >>> VARCHAR(128)
> > > >>>> ?
> > > >>>>>>>>>>>>>>>>                In most cases, the varchar length is
> not
> > > >> used
> > > >>>>>>> because
> > > >>>>>>>>>>> they
> > > >>>>>>>>>>>>>> are
> > > >>>>>>>>>>>>>>>> stored as String in Flink. But it can be used to
> > optimize
> > > >> in
> > > >>>>>> the
> > > >>>>>>>>>>>>> future
> > > >>>>>>>>>>>>>>> if
> > > >>>>>>>>>>>>>>>> we know the column is a fixed length VARCHAR.
> > > >>>>>>>>>>>>>>>>                So IMO, we can support VARCHAR with
> > length
> > > >> in
> > > >>>> the
> > > >>>>>>>>>> future,
> > > >>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>> just VARCHAR in this version.
> > > >>>>>>>>>>>>>>>>           (b) Should DECIMAL support custom scale and
> > > >>>> precision,
> > > >>>>>>>> e.g.
> > > >>>>>>>>>>>>>>>> DECIMAL(12, 5)?
> > > >>>>>>>>>>>>>>>>                If we clearly know the scale and
> > precision
> > > >> of
> > > >>>> the
> > > >>>>>>>>>>> Decimal,
> > > >>>>>>>>>>>>>> we
> > > >>>>>>>>>>>>>>>> can have some optimization on
> > > >> serialization/deserialization.
> > > >>>>>>> IMO,
> > > >>>>>>>>>> we
> > > >>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>> support just support DECIMAL in this version,
> > > >>>>>>>>>>>>>>>>                which means DECIMAL(38, 18) as default.
> > And
> > > >>>>>> support
> > > >>>>>>>>>>> custom
> > > >>>>>>>>>>>>>>> scale
> > > >>>>>>>>>>>>>>>> and precision in the future.
> > > >>>>>>>>>>>>>>>>      (2) View DDL: Do we need WITH properties in View
> > DDL
> > > >>>>>>> (proposed
> > > >>>>>>>> in
> > > >>>>>>>>>>>>>>> doc[2])?
> > > >>>>>>>>>>>>>>>> What are the properties on the view used for?
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> The features could be supported and discussed in the
> > > >> future:
> > > >>>>>>>>>>>>>>>> (1) period definition on table
> > > >>>>>>>>>>>>>>>> (2) Type DDL
> > > >>>>>>>>>>>>>>>> (3) Index DDL
> > > >>>>>>>>>>>>>>>> (4) Library DDL
> > > >>>>>>>>>>>>>>>> (5) Drop statement
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> [1] Flink DDL draft by Lin and Jark:
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1o16jC-AxnZoxMfHQptkKQkSC6ZDDBRhKg6gm8VGnY-k/edit#
> > > >>>>>>>>>>>>>>>> [2] Flink SQL DDL design by Shuyi:
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit#
> > > >>>>>>>>>>>>>>>> Cheers,
> > > >>>>>>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>> On Thu, 29 Nov 2018 at 16:13, Shaoxuan Wang <
> > > >>>>>>> [hidden email]>
> > > >>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>> Sure Shuyu,
> > > >>>>>>>>>>>>>>>>> What I hope is that we can reach an agreement on DDL
> > > >> gramma
> > > >>>>>> as
> > > >>>>>>>>>> soon
> > > >>>>>>>>>>>>>> as
> > > >>>>>>>>>>>>>>>>> possible. There are a few differences between your
> > > >> proposal
> > > >>>>>> and
> > > >>>>>>>>>>>>> ours.
> > > >>>>>>>>>>>>>>>> Once
> > > >>>>>>>>>>>>>>>>> Lin and Jark propose our design, we can quickly
> discuss
> > > >> on
> > > >>>>>> the
> > > >>>>>>>>>>>>> those
> > > >>>>>>>>>>>>>>>>> differences, and see how far away towards a unified
> > > >> design.
> > > >>>>>>>>>>>>>>>>> WRT the external catalog, I think it is an orthogonal
> > > >>> topic,
> > > >>>>>> we
> > > >>>>>>>>>> can
> > > >>>>>>>>>>>>>>>> design
> > > >>>>>>>>>>>>>>>>> it in parallel. I believe @Xuefu, @Bowen are already
> > > >>> working
> > > >>>>>>> on.
> > > >>>>>>>>>> We
> > > >>>>>>>>>>>>>>>>> should/will definitely involve them to review the
> final
> > > >>>>>> design
> > > >>>>>>> of
> > > >>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>> implementation. I would suggest that we should give
> it
> > a
> > > >>>>>> higher
> > > >>>>>>>>>>>>>>> priority
> > > >>>>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>> the DDL implementation, as it is a crucial component
> > for
> > > >>> the
> > > >>>>>>> user
> > > >>>>>>>>>>>>>>>>> experience of SQL_CLI.
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>>>>>> Shaoxuan
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>> On Thu, Nov 29, 2018 at 6:56 AM Shuyi Chen <
> > > >>>>>> [hidden email]
> > > >>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>> Thanks a lot, Shaoxuan, Jack and Lin. We should
> > > >> definitely
> > > >>>>>>>>>>>>>>> collaborate
> > > >>>>>>>>>>>>>>>>>> here, we have also our own DDL implementation
> running
> > in
> > > >>>>>>>>>>>>> production
> > > >>>>>>>>>>>>>>> for
> > > >>>>>>>>>>>>>>>>>> almost 2 years at Uber. With the joint experience
> from
> > > >>> both
> > > >>>>>>>>>>>>>>> companies,
> > > >>>>>>>>>>>>>>>> we
> > > >>>>>>>>>>>>>>>>>> can definitely make the Flink SQL DDL better.
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> As @shaoxuan suggest, Jark can come up with a doc
> that
> > > >>> talks
> > > >>>>>>>>>>>>> about
> > > >>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>> current DDL design in Alibaba, and we can discuss
> and
> > > >>> merge
> > > >>>>>>> them
> > > >>>>>>>>>>>>>> into
> > > >>>>>>>>>>>>>>>>> one,
> > > >>>>>>>>>>>>>>>>>> make it as a FLIP, and plan the tasks for
> > > >> implementation.
> > > >>>>>>> Also,
> > > >>>>>>>>>>>>> we
> > > >>>>>>>>>>>>>>>> should
> > > >>>>>>>>>>>>>>>>>> take into account the new external catalog effort in
> > the
> > > >>>>>>> design.
> > > >>>>>>>>>>>>>> What
> > > >>>>>>>>>>>>>>>> do
> > > >>>>>>>>>>>>>>>>>> you guys think?
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 6:45 AM Jark Wu <
> > > >> [hidden email]
> > > >>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>> Hi Shaoxuan,
> > > >>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>> I think summarizing it into a google doc is a good
> > > >> idea.
> > > >>> We
> > > >>>>>>>>>>>>> will
> > > >>>>>>>>>>>>>>>>> prepare
> > > >>>>>>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>>>>> in the next few days.
> > > >>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>> Thanks,
> > > >>>>>>>>>>>>>>>>>>> Jark
> > > >>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>> Shaoxuan Wang <[hidden email]> 于2018年11月28日周三
> > > >>>>>> 下午9:17写道：
> > > >>>>>>>>>>>>>>>>>>>> Hi Lin and Jark,
> > > >>>>>>>>>>>>>>>>>>>> Thanks for sharing those details. Can you please
> > > >>> consider
> > > >>>>>>>>>>>>>>>> summarizing
> > > >>>>>>>>>>>>>>>>>>> your
> > > >>>>>>>>>>>>>>>>>>>> DDL design into a google doc.
> > > >>>>>>>>>>>>>>>>>>>> We can still continue the discussions on Shuyi's
> > > >>> proposal.
> > > >>>>>>>>>>>>> But
> > > >>>>>>>>>>>>>>>>> having a
> > > >>>>>>>>>>>>>>>>>>>> separate google doc will be easy for the DEV to
> > > >>>>>>>>>>>>>>>>>>> understand/comment/discuss
> > > >>>>>>>>>>>>>>>>>>>> on your proposed DDL implementation.
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>>>>>>>>> Shaoxuan
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 7:39 PM Jark Wu <
> > > >>> [hidden email]
> > > >>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> Thanks for bringing up this discussion and the
> > > >> awesome
> > > >>>>>>>>>>>>> work!
> > > >>>>>>>>>>>>>> I
> > > >>>>>>>>>>>>>>>> have
> > > >>>>>>>>>>>>>>>>>>> left
> > > >>>>>>>>>>>>>>>>>>>>> some comments in the doc.
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> I want to share something more about the
> watermark
> > > >>>>>>>>>>>>> definition
> > > >>>>>>>>>>>>>>>>> learned
> > > >>>>>>>>>>>>>>>>>>>> from
> > > >>>>>>>>>>>>>>>>>>>>> Alibaba.
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>        1.
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>        Table should be able to accept multiple
> > > >> watermark
> > > >>>>>>>>>>>>>>> definition.
> > > >>>>>>>>>>>>>>>>>>>>>        Because a table may have more than one
> > rowtime
> > > >>>>>> field.
> > > >>>>>>>>>>>>> For
> > > >>>>>>>>>>>>>>>>> example,
> > > >>>>>>>>>>>>>>>>>>> one
> > > >>>>>>>>>>>>>>>>>>>>>        rowtime field is from existing field but
> > > >> missing
> > > >>> in
> > > >>>>>>> some
> > > >>>>>>>>>>>>>>>>> records,
> > > >>>>>>>>>>>>>>>>>>>>> another
> > > >>>>>>>>>>>>>>>>>>>>>        is the ingestion timestamp in Kafka but
> not
> > > >> very
> > > >>>>>>>>>>>>> accurate.
> > > >>>>>>>>>>>>>>> In
> > > >>>>>>>>>>>>>>>>> this
> > > >>>>>>>>>>>>>>>>>>>> case,
> > > >>>>>>>>>>>>>>>>>>>>>        user may define two rowtime fields with
> > > >>> watermarks
> > > >>>>>> in
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>> Table
> > > >>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>> choose
> > > >>>>>>>>>>>>>>>>>>>>>        one in different situation.
> > > >>>>>>>>>>>>>>>>>>>>>        2.
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>        Watermark stragety always work with
> rowtime
> > > >> field
> > > >>>>>>>>>>>>>> together.
> > > >>>>>>>>>>>>>>>>>>>>> Based on the two points metioned above, I think
> we
> > > >>> should
> > > >>>>>>>>>>>>>>> combine
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>> watermark strategy and rowtime field selection
> > (i.e.
> > > >>>>>> which
> > > >>>>>>>>>>>>>>>> existing
> > > >>>>>>>>>>>>>>>>>>> field
> > > >>>>>>>>>>>>>>>>>>>>> used to generate watermark) in one clause, so
> that
> > we
> > > >>> can
> > > >>>>>>>>>>>>>>> define
> > > >>>>>>>>>>>>>>>>>>> multiple
> > > >>>>>>>>>>>>>>>>>>>>> watermarks in one Table.
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> Here I will share the watermark syntax used in
> > > >> Alibaba
> > > >>>>>>>>>>>>>> (simply
> > > >>>>>>>>>>>>>>>>>>> modified):
> > > >>>>>>>>>>>>>>>>>>>>> watermarkDefinition:
> > > >>>>>>>>>>>>>>>>>>>>> WATERMARK [watermarkName] FOR <rowtime_field> AS
> > > >>>>>>>>>>>>> wm_strategy
> > > >>>>>>>>>>>>>>>>>>>>> wm_strategy:
> > > >>>>>>>>>>>>>>>>>>>>>       BOUNDED WITH OFFSET 'string' timeUnit
> > > >>>>>>>>>>>>>>>>>>>>> |
> > > >>>>>>>>>>>>>>>>>>>>>       ASCENDING
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> The “WATERMARK” keyword starts a watermark
> > > >> definition.
> > > >>>>>> The
> > > >>>>>>>>>>>>>>> “FOR”
> > > >>>>>>>>>>>>>>>>>>> keyword
> > > >>>>>>>>>>>>>>>>>>>>> defines which existing field used to generate
> > > >>> watermark,
> > > >>>>>>>>>>>>> this
> > > >>>>>>>>>>>>>>>> field
> > > >>>>>>>>>>>>>>>>>>>> should
> > > >>>>>>>>>>>>>>>>>>>>> already exist in the schema (we can use
> > > >> computed-column
> > > >>>>>> to
> > > >>>>>>>>>>>>>>> derive
> > > >>>>>>>>>>>>>>>>>> from
> > > >>>>>>>>>>>>>>>>>>>>> other fields). The “AS” keyword defines watermark
> > > >>>>>> strategy,
> > > >>>>>>>>>>>>>>> such
> > > >>>>>>>>>>>>>>>> as
> > > >>>>>>>>>>>>>>>>>>>> BOUNDED
> > > >>>>>>>>>>>>>>>>>>>>> WITH OFFSET (covers almost all the requirements)
> > and
> > > >>>>>>>>>>>>>> ASCENDING.
> > > >>>>>>>>>>>>>>>>>>>>> When the expected rowtime field does not exist in
> > the
> > > >>>>>>>>>>>>> schema,
> > > >>>>>>>>>>>>>>> we
> > > >>>>>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>>>>> use
> > > >>>>>>>>>>>>>>>>>>>>> computed-column syntax to derive it from other
> > > >> existing
> > > >>>>>>>>>>>>>> fields
> > > >>>>>>>>>>>>>>>>> using
> > > >>>>>>>>>>>>>>>>>>>>> built-in functions or user defined functions. So
> > the
> > > >>>>>>>>>>>>>>>>>> rowtime/watermark
> > > >>>>>>>>>>>>>>>>>>>>> definition doesn’t need to care about
> > “field-change”
> > > >>>>>>>>>>>>> strategy
> > > >>>>>>>>>>>>>>>>>>>>> (replace/add/from-field). And the proctime field
> > > >>>>>> definition
> > > >>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>>> also
> > > >>>>>>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>>>>>> defined using computed-column. Such as pt as
> > > >> PROCTIME()
> > > >>>>>>>>>>>>> which
> > > >>>>>>>>>>>>>>>>>> defines a
> > > >>>>>>>>>>>>>>>>>>>>> proctime field named “pt” in the schema.
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> Looking forward to working with you guys!
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> Best,
> > > >>>>>>>>>>>>>>>>>>>>> Jark Wu
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>> Lin Li <[hidden email]> 于2018年11月28日周三
> > > >>> 下午6:33写道：
> > > >>>>>>>>>>>>>>>>>>>>>> @Shuyi
> > > >>>>>>>>>>>>>>>>>>>>>> Thanks for the proposal!  We have a simple DDL
> > > >>>>>>>>>>>>>> implementation
> > > >>>>>>>>>>>>>>>>>>> (extends
> > > >>>>>>>>>>>>>>>>>>>>>> Calcite's parser) which been running for almost
> > two
> > > >>>>>> years
> > > >>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>>>> production
> > > >>>>>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>> works well.
> > > >>>>>>>>>>>>>>>>>>>>>> I think the most valued things we'd learned is
> > > >> keeping
> > > >>>>>>>>>>>>>>>> simplicity
> > > >>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>> standard compliance.
> > > >>>>>>>>>>>>>>>>>>>>>> Here's the approximate grammar, FYI
> > > >>>>>>>>>>>>>>>>>>>>>> CREATE TABLE
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> CREATE TABLE tableName(
> > > >>>>>>>>>>>>>>>>>>>>>>             columnDefinition [,
> columnDefinition]*
> > > >>>>>>>>>>>>>>>>>>>>>>             [ computedColumnDefinition [,
> > > >>>>>>>>>>>>>>>> computedColumnDefinition]*
> > > >>>>>>>>>>>>>>>>> ]
> > > >>>>>>>>>>>>>>>>>>>>>>             [ tableConstraint [,
> > tableConstraint]* ]
> > > >>>>>>>>>>>>>>>>>>>>>>             [ tableIndex [, tableIndex]* ]
> > > >>>>>>>>>>>>>>>>>>>>>>         [ PERIOD FOR SYSTEM_TIME ]
> > > >>>>>>>>>>>>>>>>>>>>>>             [ WATERMARK watermarkName FOR
> > > >> rowTimeColumn
> > > >>>> AS
> > > >>>>>>>>>>>>>>>>>>>>>> withOffset(rowTimeColumn, offset) ]     ) [
> WITH (
> > > >>>>>>>>>>>>>>> tableOption
> > > >>>>>>>>>>>>>>>> [
> > > >>>>>>>>>>>>>>>>> ,
> > > >>>>>>>>>>>>>>>>>>>>>> tableOption]* ) ] [ ; ]
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> columnDefinition ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             columnName dataType [ NOT NULL ]
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> dataType  ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             {
> > > >>>>>>>>>>>>>>>>>>>>>>               [ VARCHAR ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ BOOLEAN ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ TINYINT ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ SMALLINT ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ INT ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ BIGINT ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ FLOAT ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ DECIMAL ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ DOUBLE ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ DATE ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ TIME ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ TIMESTAMP ]
> > > >>>>>>>>>>>>>>>>>>>>>>               | [ VARBINARY ]
> > > >>>>>>>>>>>>>>>>>>>>>>             }
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> computedColumnDefinition ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             columnName AS
> computedColumnExpression
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> tableConstraint ::=
> > > >>>>>>>>>>>>>>>>>>>>>>         { PRIMARY KEY | UNIQUE }
> > > >>>>>>>>>>>>>>>>>>>>>>             (columnName [, columnName]* )
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> tableIndex ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             [ UNIQUE ] INDEX indexName
> > > >>>>>>>>>>>>>>>>>>>>>>              (columnName [, columnName]* )
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> rowTimeColumn ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             columnName
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> tableOption ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             property=value
> > > >>>>>>>>>>>>>>>>>>>>>>             offset ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             positive integer (unit: ms)
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> CREATE VIEW
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> CREATE VIEW viewName
> > > >>>>>>>>>>>>>>>>>>>>>>       [
> > > >>>>>>>>>>>>>>>>>>>>>>             ( columnName [, columnName]* )
> > > >>>>>>>>>>>>>>>>>>>>>>       ]
> > > >>>>>>>>>>>>>>>>>>>>>>             AS queryStatement;
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> CREATE FUNCTION
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>      CREATE FUNCTION functionName
> > > >>>>>>>>>>>>>>>>>>>>>>       AS 'className';
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>      className ::=
> > > >>>>>>>>>>>>>>>>>>>>>>             fully qualified name
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>> Shuyi Chen <[hidden email]> 于2018年11月28日周三
> > > >>>>>> 上午3:28写道：
> > > >>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Timo and Xuefu. Yes, I think we
> can
> > > >>>>>>>>>>>>>> finalize
> > > >>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> design
> > > >>>>>>>>>>>>>>>>>>>>> doc
> > > >>>>>>>>>>>>>>>>>>>>>>> first and start implementation w/o the unified
> > > >>>>>>>>>>>>> connector
> > > >>>>>>>>>>>>>>> API
> > > >>>>>>>>>>>>>>>>>> ready
> > > >>>>>>>>>>>>>>>>>>> by
> > > >>>>>>>>>>>>>>>>>>>>>>> skipping some featue.
> > > >>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>> Xuefu, I like the idea of making Flink specific
> > > >>>>>>>>>>>>>> properties
> > > >>>>>>>>>>>>>>>> into
> > > >>>>>>>>>>>>>>>>>>>> generic
> > > >>>>>>>>>>>>>>>>>>>>>>> key-value pairs, so that it will make
> integration
> > > >>> with
> > > >>>>>>>>>>>>>> Hive
> > > >>>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>> (or
> > > >>>>>>>>>>>>>>>>>>>>>> others,
> > > >>>>>>>>>>>>>>>>>>>>>>> e.g. Beam DDL) easier.
> > > >>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>> I'll run a final pass over the design doc and
> > > >>> finalize
> > > >>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>> design
> > > >>>>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>> next few days. And we can start creating tasks
> > and
> > > >>>>>>>>>>>>>>>> collaborate
> > > >>>>>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>> implementation. Thanks a lot for all the
> comments
> > > >> and
> > > >>>>>>>>>>>>>>> inputs.
> > > >>>>>>>>>>>>>>>>>>>>>>> Cheers!
> > > >>>>>>>>>>>>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>> On Tue, Nov 27, 2018 at 7:02 AM Zhang, Xuefu <
> > > >>>>>>>>>>>>>>>>>>>> [hidden email]>
> > > >>>>>>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> Yeah! I agree with Timo that DDL can actually
> > > >>> proceed
> > > >>>>>>>>>>>>>> w/o
> > > >>>>>>>>>>>>>>>>> being
> > > >>>>>>>>>>>>>>>>>>>>> blocked
> > > >>>>>>>>>>>>>>>>>>>>>>> by
> > > >>>>>>>>>>>>>>>>>>>>>>>> connector API. We can leave the unknown out
> > while
> > > >>>>>>>>>>>>>>> defining
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>> basic
> > > >>>>>>>>>>>>>>>>>>>>>>> syntax.
> > > >>>>>>>>>>>>>>>>>>>>>>>> @Shuyi
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> As commented in the doc, I think we can
> probably
> > > >>>>>>>>>>>>> stick
> > > >>>>>>>>>>>>>>> with
> > > >>>>>>>>>>>>>>>>>>> simple
> > > >>>>>>>>>>>>>>>>>>>>>> syntax
> > > >>>>>>>>>>>>>>>>>>>>>>>> with general properties, without extending the
> > > >>> syntax
> > > >>>>>>>>>>>>>> too
> > > >>>>>>>>>>>>>>>>> much
> > > >>>>>>>>>>>>>>>>>>> that
> > > >>>>>>>>>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>>>>>>>>>> mimics the descriptor API.
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> Part of our effort on Flink-Hive integration
> is
> > > >> also
> > > >>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>> make
> > > >>>>>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>>>>> syntax
> > > >>>>>>>>>>>>>>>>>>>>>>>> compatible with Hive's. The one in the current
> > > >>>>>>>>>>>>> proposal
> > > >>>>>>>>>>>>>>>> seems
> > > >>>>>>>>>>>>>>>>>>>> making
> > > >>>>>>>>>>>>>>>>>>>>>> our
> > > >>>>>>>>>>>>>>>>>>>>>>>> effort more challenging.
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> We can help and collaborate. At this moment, I
> > > >> think
> > > >>>>>>>>>>>>> we
> > > >>>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>>>>>> finalize
> > > >>>>>>>>>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>>>>>>>>> the proposal and then we can divide the tasks
> > for
> > > >>>>>>>>>>>>>> better
> > > >>>>>>>>>>>>>>>>>>>>> collaboration.
> > > >>>>>>>>>>>>>>>>>>>>>>>> Please let me know if there are  any questions
> > or
> > > >>>>>>>>>>>>>>>>> suggestions.
> > > >>>>>>>>>>>>>>>>>>>>>>>> Thanks,
> > > >>>>>>>>>>>>>>>>>>>>>>>> Xuefu
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>
> ------------------------------------------------------------------
> > > >>>>>>>>>>>>>>>>>>>>>>>> Sender:Timo Walther <[hidden email]>
> > > >>>>>>>>>>>>>>>>>>>>>>>> Sent at:2018 Nov 27 (Tue) 16:21
> > > >>>>>>>>>>>>>>>>>>>>>>>> Recipient:dev <[hidden email]>
> > > >>>>>>>>>>>>>>>>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> Thanks for offering your help here, Xuefu. It
> > > >> would
> > > >>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>> great
> > > >>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>>> move
> > > >>>>>>>>>>>>>>>>>>>>>>>> these efforts forward. I agree that the DDL is
> > > >>>>>>>>>>>>> somehow
> > > >>>>>>>>>>>>>>>>> releated
> > > >>>>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>>> unified connector API design but we can also
> > start
> > > >>>>>>>>>>>>> with
> > > >>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>> basic
> > > >>>>>>>>>>>>>>>>>>>>>>>> functionality now and evolve the DDL during
> this
> > > >>>>>>>>>>>>>> release
> > > >>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>> next
> > > >>>>>>>>>>>>>>>>>>>>>>> releases.
> > > >>>>>>>>>>>>>>>>>>>>>>>> For example, we could identify the MVP DDL
> > syntax
> > > >>>>>>>>>>>>> that
> > > >>>>>>>>>>>>>>>> skips
> > > >>>>>>>>>>>>>>>>>>>> defining
> > > >>>>>>>>>>>>>>>>>>>>>>>> key constraints and maybe even time
> attributes.
> > > >> This
> > > >>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>> could
> > > >>>>>>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>>>>>> used
> > > >>>>>>>>>>>>>>>>>>>>>>>> for batch usecases, ETL, and materializing SQL
> > > >>>>>>>>>>>>> queries
> > > >>>>>>>>>>>>>>> (no
> > > >>>>>>>>>>>>>>>>> time
> > > >>>>>>>>>>>>>>>>>>>>>>>> operations like windows).
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> The unified connector API is high on our
> > priority
> > > >>>>>>>>>>>>> list
> > > >>>>>>>>>>>>>>> for
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> 1.8
> > > >>>>>>>>>>>>>>>>>>>>>>>> release. I will try to update the document
> until
> > > >> mid
> > > >>>>>>>>>>>>> of
> > > >>>>>>>>>>>>>>>> next
> > > >>>>>>>>>>>>>>>>>>> week.
> > > >>>>>>>>>>>>>>>>>>>>>>>> Regards,
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> Timo
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>> Am 27.11.18 um 08:08 schrieb Shuyi Chen:
> > > >>>>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Xuefu. I was busy for some
> other
> > > >>>>>>>>>>>>> stuff
> > > >>>>>>>>>>>>>>> for
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>> last 2
> > > >>>>>>>>>>>>>>>>>>>>>>>> weeks,
> > > >>>>>>>>>>>>>>>>>>>>>>>>> but we are definitely interested in moving
> this
> > > >>>>>>>>>>>>>>> forward.
> > > >>>>>>>>>>>>>>>> I
> > > >>>>>>>>>>>>>>>>>>> think
> > > >>>>>>>>>>>>>>>>>>>>> once
> > > >>>>>>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>>>> unified connector API design [1] is done, we
> > can
> > > >>>>>>>>>>>>>>> finalize
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>>>>>>> design
> > > >>>>>>>>>>>>>>>>>>>>>>>> as
> > > >>>>>>>>>>>>>>>>>>>>>>>>> well and start creating concrete subtasks to
> > > >>>>>>>>>>>>>>> collaborate
> > > >>>>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>>>> implementation with the community.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>> Shuyi
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>>>>>> On Mon, Nov 26, 2018 at 7:01 PM Zhang, Xuefu
> <
> > > >>>>>>>>>>>>>>>>>>>>>> [hidden email]>
> > > >>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> I'm wondering if you folks still have the
> > > >>>>>>>>>>>>> bandwidth
> > > >>>>>>>>>>>>>>>>> working
> > > >>>>>>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>>>>>> this.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> We have some dedicated resource and like to
> > move
> > > >>>>>>>>>>>>>> this
> > > >>>>>>>>>>>>>>>>>> forward.
> > > >>>>>>>>>>>>>>>>>>>> We
> > > >>>>>>>>>>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> collaborate.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Thanks,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>
> > ------------------------------------------------------------------
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 发件人：wenlong.lwl<[hidden email]>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 日 期：2018年11月05日 11:15:35
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 收件人：<[hidden email]>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 主 题：Re: [DISCUSS] Flink SQL DDL Design
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Hi, Shuyi, thanks for the proposal.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> I have two concerns about the table ddl:
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 1. how about remove the source/sink mark
> from
> > > >> the
> > > >>>>>>>>>>>>>> ddl,
> > > >>>>>>>>>>>>>>>>>> because
> > > >>>>>>>>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>>>>>>> is
> > > >>>>>>>>>>>>>>>>>>>>>>> not
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> necessary, the framework determine the table
> > > >>>>>>>>>>>>>> referred
> > > >>>>>>>>>>>>>>>> is a
> > > >>>>>>>>>>>>>>>>>>>> source
> > > >>>>>>>>>>>>>>>>>>>>>> or a
> > > >>>>>>>>>>>>>>>>>>>>>>>> sink
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> according to the context of the query using
> > the
> > > >>>>>>>>>>>>>> table.
> > > >>>>>>>>>>>>>>>> it
> > > >>>>>>>>>>>>>>>>>> will
> > > >>>>>>>>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>>>>>>> more
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> convenient for use defining a table which
> can
> > be
> > > >>>>>>>>>>>>>> both
> > > >>>>>>>>>>>>>>> a
> > > >>>>>>>>>>>>>>>>>> source
> > > >>>>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>>> sink,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> and more convenient for catalog to
> persistent
> > > >> and
> > > >>>>>>>>>>>>>>> manage
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>> meta
> > > >>>>>>>>>>>>>>>>>>>>>>> infos.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 2. how about just keeping one pure string
> map
> > as
> > > >>>>>>>>>>>>>>>>> parameters
> > > >>>>>>>>>>>>>>>>>>> for
> > > >>>>>>>>>>>>>>>>>>>>>> table,
> > > >>>>>>>>>>>>>>>>>>>>>>>> like
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> create tabe Kafka10SourceTable (
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> intField INTEGER,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> stringField VARCHAR(128),
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> longField BIGINT,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> rowTimeField TIMESTAMP
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> ) with (
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.type = ’kafka’,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.property-version = ’1’,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.version = ’0.10’,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.topic =
> > ‘test-kafka-topic’,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.startup-mode =
> > > >>>>>>>>>>>>> ‘latest-offset’,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.specific-offset =
> > ‘offset’,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> format.type = 'json'
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> format.prperties.version=’1’,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> format.derive-schema = 'true'
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> );
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Because:
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 1. in TableFactory, what user use is a
> string
> > > >> map
> > > >>>>>>>>>>>>>>>>>> properties,
> > > >>>>>>>>>>>>>>>>>>>>>> defining
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> parameters by string-map can be the closest
> > way
> > > >> to
> > > >>>>>>>>>>>>>>>> mapping
> > > >>>>>>>>>>>>>>>>>> how
> > > >>>>>>>>>>>>>>>>>>>>> user
> > > >>>>>>>>>>>>>>>>>>>>>>> use
> > > >>>>>>>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> parameters.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 2. The table descriptor can be extended by
> > user,
> > > >>>>>>>>>>>>>> like
> > > >>>>>>>>>>>>>>>> what
> > > >>>>>>>>>>>>>>>>>> is
> > > >>>>>>>>>>>>>>>>>>>> done
> > > >>>>>>>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>>>>>> Kafka
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> and Json, it means that the parameter keys
> in
> > > >>>>>>>>>>>>>>> connector
> > > >>>>>>>>>>>>>>>> or
> > > >>>>>>>>>>>>>>>>>>>> format
> > > >>>>>>>>>>>>>>>>>>>>>> can
> > > >>>>>>>>>>>>>>>>>>>>>>> be
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> different in different implementation, we
> can
> > > >> not
> > > >>>>>>>>>>>>>>>> restrict
> > > >>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>> key
> > > >>>>>>>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>>>>> a
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> specified set, so we need a map in connector
> > > >> scope
> > > >>>>>>>>>>>>>>> and a
> > > >>>>>>>>>>>>>>>>> map
> > > >>>>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties scope. why not just
> give
> > > >>>>>>>>>>>>> user a
> > > >>>>>>>>>>>>>>>>> single
> > > >>>>>>>>>>>>>>>>>>> map,
> > > >>>>>>>>>>>>>>>>>>>>> let
> > > >>>>>>>>>>>>>>>>>>>>>>>> them
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> put parameters in a format they like, which
> is
> > > >>>>>>>>>>>>> also
> > > >>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> simplest
> > > >>>>>>>>>>>>>>>>>>>>> way
> > > >>>>>>>>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> implement DDL parser.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> 3. whether we can define a format clause or
> > not,
> > > >>>>>>>>>>>>>>> depends
> > > >>>>>>>>>>>>>>>>> on
> > > >>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> implementation of the connector, using
> > different
> > > >>>>>>>>>>>>>>> clause
> > > >>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>>>> may
> > > >>>>>>>>>>>>>>>>>>>>>>> make
> > > >>>>>>>>>>>>>>>>>>>>>>>> a
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> misunderstanding that we can combine the
> > > >>>>>>>>>>>>> connectors
> > > >>>>>>>>>>>>>>> with
> > > >>>>>>>>>>>>>>>>>>>> arbitrary
> > > >>>>>>>>>>>>>>>>>>>>>>>> formats,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> which may not work actually.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> On Sun, 4 Nov 2018 at 18:25, Dominik
> Wosiński
> > <
> > > >>>>>>>>>>>>>>>>>>> [hidden email]
> > > >>>>>>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> +1, Thanks for the proposal.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> I guess this is a long-awaited change. This
> > can
> > > >>>>>>>>>>>>>>> vastly
> > > >>>>>>>>>>>>>>>>>>> increase
> > > >>>>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> functionalities of the SQL Client as it
> will
> > be
> > > >>>>>>>>>>>>>>>> possible
> > > >>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>> use
> > > >>>>>>>>>>>>>>>>>>>>>>> complex
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> extensions like for example those provided
> by
> > > >>>>>>>>>>>>>> Apache
> > > >>>>>>>>>>>>>>>>>>> Bahir[1].
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> Best Regards,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> Dom.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> https://github.com/apache/bahir-flink
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> sob., 3 lis 2018 o 17:17 Rong Rong <
> > > >>>>>>>>>>>>>>>> [hidden email]>
> > > >>>>>>>>>>>>>>>>>>>>>> napisał(a):
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> +1. Thanks for putting the proposal
> together
> > > >>>>>>>>>>>>>> Shuyi.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL has been brought up in a couple of
> times
> > > >>>>>>>>>>>>>>>> previously
> > > >>>>>>>>>>>>>>>>>>> [1,2].
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Utilizing
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL will definitely be a great extension
> to
> > > >> the
> > > >>>>>>>>>>>>>>>> current
> > > >>>>>>>>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>>>>>>>> SQL
> > > >>>>>>>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> systematically support some of the
> > previously
> > > >>>>>>>>>>>>>>> brought
> > > >>>>>>>>>>>>>>>> up
> > > >>>>>>>>>>>>>>>>>>>>> features
> > > >>>>>>>>>>>>>>>>>>>>>>> such
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> as
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]. And it will also be beneficial to see
> > the
> > > >>>>>>>>>>>>>>>> document
> > > >>>>>>>>>>>>>>>>>>>> closely
> > > >>>>>>>>>>>>>>>>>>>>>>>> aligned
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> with the previous discussion for unified
> SQL
> > > >>>>>>>>>>>>>>> connector
> > > >>>>>>>>>>>>>>>>> API
> > > >>>>>>>>>>>>>>>>>>>> [4].
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> I also left a few comments on the doc.
> > Looking
> > > >>>>>>>>>>>>>>> forward
> > > >>>>>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>>>>>>> alignment
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> with the other couple of efforts and
> > > >>>>>>>>>>>>> contributing
> > > >>>>>>>>>>>>>> to
> > > >>>>>>>>>>>>>>>>> them!
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> Best,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> Rong
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201805.mbox/%3CCAMZk55ZTJA7MkCK1Qu4gLPu1P9neqCfHZtTcgLfrFjfO4Xv5YQ%40mail.gmail.com%3E
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3CDC070534-0782-4AFD-8A85-8A82B384B8F7%40gmail.com%3E
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
> > > >>>>>>>>>>>>>>> https://issues.apache.org/jira/browse/FLINK-8003
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> [4]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3C6676cb66-6f31-23e1-eff5-2e9c19f88483@...%3E
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> On Fri, Nov 2, 2018 at 10:22 AM Bowen Li <
> > > >>>>>>>>>>>>>>>>>>> [hidden email]
> > > >>>>>>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks Shuyi!
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> I left some comments there. I think the
> > > >> design
> > > >>>>>>>>>>>>> of
> > > >>>>>>>>>>>>>>> SQL
> > > >>>>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> Flink-Hive
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration/External catalog enhancements
> > > >> will
> > > >>>>>>>>>>>>>> work
> > > >>>>>>>>>>>>>>>>>> closely
> > > >>>>>>>>>>>>>>>>>>>>> with
> > > >>>>>>>>>>>>>>>>>>>>>>> each
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> other. Hope we are well aligned on the
> > > >>>>>>>>>>>>> directions
> > > >>>>>>>>>>>>>>> of
> > > >>>>>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> two
> > > >>>>>>>>>>>>>>>>>>>>>>> designs,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> and I
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> look forward to working with you guys on
> > > >> both!
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bowen
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Thu, Nov 1, 2018 at 10:57 PM Shuyi
> Chen
> > <
> > > >>>>>>>>>>>>>>>>>>>> [hidden email]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi everyone,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL DDL support has been a long-time ask
> > > >> from
> > > >>>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>>> community.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> Current
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL support only DML (e.g. SELECT and
> > INSERT
> > > >>>>>>>>>>>>>>>>>> statements).
> > > >>>>>>>>>>>>>>>>>>> In
> > > >>>>>>>>>>>>>>>>>>>>> its
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> current
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> form, Flink SQL users still need to
> > > >>>>>>>>>>>>>> define/create
> > > >>>>>>>>>>>>>>>>> table
> > > >>>>>>>>>>>>>>>>>>>>> sources
> > > >>>>>>>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> sinks
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> programmatically in Java/Scala. Also, in
> > SQL
> > > >>>>>>>>>>>>>>> Client,
> > > >>>>>>>>>>>>>>>>>>> without
> > > >>>>>>>>>>>>>>>>>>>>> DDL
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> support,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the current implementation does not
> allow
> > > >>>>>>>>>>>>>>> dynamical
> > > >>>>>>>>>>>>>>>>>>> creation
> > > >>>>>>>>>>>>>>>>>>>>> of
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>> table,
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> type
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> or functions with SQL, this adds
> friction
> > > >> for
> > > >>>>>>>>>>>>>> its
> > > >>>>>>>>>>>>>>>>>>> adoption.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I drafted a design doc [1] with a few
> > other
> > > >>>>>>>>>>>>>>>> community
> > > >>>>>>>>>>>>>>>>>>>> members
> > > >>>>>>>>>>>>>>>>>>>>>> that
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> proposes
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the design and implementation for adding
> > DDL
> > > >>>>>>>>>>>>>>> support
> > > >>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>> Flink.
> > > >>>>>>>>>>>>>>>>>>>>>> The
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> initial
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> design considers DDL for table, view,
> > type,
> > > >>>>>>>>>>>>>>> library
> > > >>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>> function.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> It
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> will
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> be great to get feedback on the design
> > from
> > > >>>>>>>>>>>>> the
> > > >>>>>>>>>>>>>>>>>> community,
> > > >>>>>>>>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>>>>>>>>>>> align
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> with
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> latest effort in unified SQL connector
> API
> > > >> [2]
> > > >>>>>>>>>>>>>> and
> > > >>>>>>>>>>>>>>>>> Flink
> > > >>>>>>>>>>>>>>>>>>>> Hive
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3].
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Any feedback is highly appreciated.
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi Chen
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> > > >>
> > >
> >
> https://docs.google.com/document/d/1SkppRD_rE3uOKSN-LuZCqn4f7dz0zW5aa6T_hBZq5_o/edit?usp=sharing
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> --
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
> > > >>>>>>>>>>>>> somehow
> > > >>>>>>>>>>>>>>>>> connect
> > > >>>>>>>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>>>>>> your
> > > >>>>>>>>>>>>>>>>>>>>>>>>>>>> future."
> > > >>>>>>>>>>>>>>>>>>>>>>> --
> > > >>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
> somehow
> > > >>>>>>>>>>>>> connect
> > > >>>>>>>>>>>>>> in
> > > >>>>>>>>>>>>>>>>> your
> > > >>>>>>>>>>>>>>>>>>>>> future."
> > > >>>>>>>>>>>>>>>>>> --
> > > >>>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow
> > connect
> > > >>> in
> > > >>>>>>> your
> > > >>>>>>>>>>>>>>>> future."
> > > >>>>>>>>>>>>> --
> > > >>>>>>>>>>>>> "So you have to trust that the dots will somehow connect
> in
> > > >>> your
> > > >>>>>>>>>>> future."
> > > >>>>>>>>>>>
> > > >>>>
> > > >>> --
> > > >>> "So you have to trust that the dots will somehow connect in your
> > > future."
> > > >>>
> > >
> > >
> >
> > --
> > "So you have to trust that the dots will somehow connect in your future."
> >
>

[Timo Walther-2]

Hi all,

I think we should discuss what we consider an MVP DDL. For me, an MVP
DDL was to just focus on a CREATE TABLE statement. It would be great to
come up with a solution that finally solves the issue of connecting
different kind of systems. One reason why we postponed DDL statements
for quite some time is that we cannot change it easily once released.

However, the current state of the discussion can be summarized by the
following functionality:

1. Only support append source tables (because the distinction of
update/retract table is not clear).
2. Only support append and update sink tables (because a changeflag is
missing).
3. Don't support outputting to Kafka with time attributes (because we
cannot set a timestamp).

Personally, I would like to have more use cases enabled by solving the
header timestamps and change flag discussion. And I don't see a reason
why we have to rush here.

8). Support row/map/array data type
How do we want to support object arrays vs. primitive arrays? Currently,
we need to make this clear distinction for between external system and
Java [1] (E.g. byte[] arrays vs. object arrays) and users can choose
between Types.PRIMITIVE_ARRAY and Types.OBJECT_ARRAY. Otherwise we need
to support NULL/NOT NULL for array elements.

4) Event-Time Attributes and Watermarks
I completely agree with Rong here. `ts AS SYSTEMROWTIME()` indicates
that the system takes care of this column and for unification this would
mean both for sources and sinks. It is still a computed column but gives
hints to connectors. Implementing connectors can choose if they want to
use this hint or not. The Flink Kafka connector would make use of it.
@Jark: I think a PERSISTED keyword would confuse users (as shown by your
Stackoverflow question) and would only make sense for SYSTEMROWTIME and
no other computed column.

3) SOURCE / SINK / BOTH
@Jark: My initial suggestion was to make the SOURCE/SINK optional such
that users can only use CREATE TABLE depending on the use case. But as I
said before, since I cannot find support here, we can drop the keywords.

7) Table Update Mode
@Jark: The questions that you posted are exactly the ones that we should
find an answer for. Because a DDL should just be the front end to the
characteristics of an engine. After thinking about it again a change
flag is actually more similar to a PARTITION BY clause because it
defines a field that is not in the table's schema but in the schema of
the physical format. However, the columns defined by a PARTITION BY are
shown when describing/projecting a table whereas a change flag column
must not be shown.

If a table source supports append, upserts, and retractions, we need a
way to express how we want to connect to the system.

hasPrimaryKey() && !hasChangeFlag() -> append mode
hasPrimaryKey() && hasChangeFlag() -> upsert mode
!hasPrimaryKey() && hasChangeFlag() -> retract mode

Are we fine with this?

Regarding reading `topic`, `partition`, `offset` or custom properties
from message headers. I already discussed this in my unified connector
document. We don't need built-in functions for all these properties.
Those things depend on the connector and format, it is their
responsibility to extend the table schema in order to expose those
properties (e.g. by providing a Map<String, String> for all these kind
of properties).

Example:

CREATE TABLE myTopic (
     col1 INT,
     col2 VARCHAR,
     col3 MAP<VARCHAR, VARCHAR>,
     col4 AS SYSTEMROWTIME()
)
PARTITION BY (col0 LONG)
WITH (
   connector.type = kafka
   format.type = key-value-metadata
   format.key-format.type = avro
   format.value-format.type = json
)

The format defines to use a KeyedDeserializationSchema that extends the
schema by a metadata column. The PARTITION BY declares the columns for
Kafka's key in Avro format. col1 till col2 are Kafka's JSON columns.

Thanks for your feedback,
Timo

[1]
https://ci.apache.org/projects/flink/flink-docs-release-1.7/dev/table/connect.html#type-strings


Am 13.12.18 um 09:50 schrieb Jark Wu:

> Hi all,
>
> Here are a bunch of my thoughts:
>
> 8). support row/map/array data type
> That's fine with me if we want to support them in the MVP. In my mind, we
> can have the field type syntax like this:
>
> ```
> filedType ::=
>              {
>                  simpleType
>               | MAP<simpleType, fieldType>
>               | ARRAY<fieldType>
>               | ROW<columnDefinition [, columnDefinition]*>
>              }
> ```
>
> I have included this in @Shuyi's summary doc [1] . Please leave feedbacks
> there!
>
> [1]
> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit
>
> 3) SOURCE / SINK / BOTH
> @Timo, CREATE TABLE statement is registering a virtual table in the session
> or catalog. I don't think it is immutable, as we might also want to support
> CREATE INDEX statements in the future. On the other hand, ACL is not a part
> of the table definition, it should belong to the permission system which is
> usually stored in somewhere else. So GRANT/INVOKE sounds like a more
> standard option.
>
> 7) Table Update Mode
> I agree with @Shuyi that table update mode can be left out from the MVP.
> Because IMO, the update mode will not break the current MVP design. It
> should be something to add, like the CHANGE_FLAG you proposed. We can
> continue this discussion when we finalize the MVP.
>
> Meanwhile, the update mode is a big topic which may involve several weeks
> to discuss. For example, (a) do we support CHANGE_FLAG when the table
> supports upsert (or when the table defined a primary key)?  (b) the
> CHANGE_FLAG should support write and read both. (c) currently, we only
> support true (add) and false (retract) flag type, are they enough? (d) How
> to connect an external storage which also support insert/delete flag like
> mysql binlog?
>
> Regarding to the CHANGE_FLAG @Timo proposed, I think this is a good
> direction. But should isRetraction be a physical field and make CHANGE_FLAG
> like a constraint on that? If yes, then what the type of isRetraction?
>
> 4.b) Ingesting and writing timestamps to systems.
> @Shuyi, PERSISTED can solve the problem of the field is not physically
> stored. However, it doesn't solve the problem that how to write a field
> back to the computed column, because "A computed column cannot be the
> target of an INSERT or UPDATE statement" even if the computed column is
> persisted. If we want to write a rowtime back the the external system, the
> DML should look like this: "INSERT INTO sink SELECT a, rowtime FROM
> source". The point is that the `rowtime` must be specified in the INSERT
> statement, that's why I hope the `rowtime` field in Table is not a computed
> column. See more information about PERSISTED [2] [3].
>
> Another point to consider is SYSTEMROWTIME() only solve reading timestamp
> from message header in systems. There are many similar requirements here,
> such as reading `topic`, `partition`, `offset` or custom properties from
> message headers, do we plan to support a bunch of built-in functions like
> SYSTEMROWTIME()?  Do we have some clean and easy way for this?
>
> [2]:
> https://docs.microsoft.com/en-us/sql/t-sql/statements/alter-table-computed-column-definition-transact-sql?view=sql-server-2017
> [3]:
> https://stackoverflow.com/questions/51390531/sql-server-persisted-computed-columns-versus-actual-normal-column
>
> Looking forward to collaborate with you guys!
>
> Best,
> Jark
>
>
> On Thu, 13 Dec 2018 at 01:38, Rong Rong <[hidden email]> wrote:
>
>> Thanks for the summary effort @shuyi. Sorry for jumping in the discussion
>> so late.
>>
>> As of the scope of MVP, I think we might want to consider adding "table
>> update mode" problem to it. I agree with @timo that might not be easily
>> changed in the future if the flags has to be part of the schema/column
>> definition.
>>
>> Regarding the components under discussion.
>> 4) Event-Time Attributes and Watermarks
>> b, c) I actually like the special indicator way @fabian suggested to hint
>> Flink to read time attributes directly from the system not the data `(ts AS
>> SYSTEMROWTIME())`. It should also address the "compute field not emitted"
>> problem by carrying the "virtual column" concept like @shuyi suggested.
>> However if I understand correctly, this also required to be defined as part
>> of the schema/column definition.
>>
>> 3) SOURCE / SINK / BOTH
>> +1 on not adding properties to `CREATE TABLE` to manage ACL/permission.
>>
>> On a higher level, I think one question I have is whether we can
>> definitively come to an agreement that the features under discussion (and
>> potential solutions) can be cleanly adjusted/added from what we are
>> providing on MVP (e.g. the schema/column definition might be hard to
>> achieve but if we all agree ACL/permission should not be part of the
>> `CREATE TABLE` and a decision can be made later). @shuyi I can also help in
>> drafting the FLIP doc by summarizing the features under discussion and the
>> concerns to whether included in the MVP, so that we can carry on the
>> discussions alongside with the MVP implementation effort. I think each one
>> of these features deserves a subsection dedicated for it.
>>
>> Many thanks,
>> Rong
>>
>>
>> On Wed, Dec 12, 2018 at 1:14 AM Shuyi Chen <[hidden email]> wrote:
>>
>>> Hi all,
>>>
>>> I summarize the MVP based on the features that we agreed upon. For table
>>> update mode and custom watermark strategy and ts extractor, I found there
>>> are some discussions, so I decided to leave them out for the MVP.
>>> For row/map/array data type, I think we can add it as well if everyone
>>> agrees.
>>>
>>>
>>> 4) Event-Time Attributes and Watermarks
>>> Cited from SQL Server 2017 document (
>>>
>>>
>> https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2017
>>> ),
>>> "A
>>> computed column is a virtual column that is not physically stored in the
>>> table, unless the column is marked PERSISTED. A computed column
>> expression
>>> can use data from other columns to calculate a value for the column to
>>> which it belongs. " I think we can also use introduce the PERSISTED
>> keyword
>>> for computed column to indicate that the field can be stored back to the
>>> table, i.e. ts AS SYSTEMROWTIME() PERSISTED.
>>>
>>> 3) SOURCE / SINK / BOTH
>>> GRANT/INVOKE sounds like a more standard option than adding a property to
>>> CREATE TABLE to manage the ACL/permission. The ACL can be stored
>> somewhere
>>> in a database, and allow/disallow access to a dynamic table depending on
>>> whether it's a "INSERT INTO" or "SELECT".
>>>
>>> I can volunteer to put the discussion as a FLIP.  I can try to summarize
>>> the current discussion, and share edit permission with you to collaborate
>>> on the documents. After we finalized the doc, we can publish it as a
>> FLIP.
>>> What do you think?
>>>
>>> Shuyi
>>>
>>>
>>>
>>> On Tue, Dec 11, 2018 at 9:13 AM Timo Walther <[hidden email]> wrote:
>>>
>>>> Hi all,
>>>>
>>>> thanks for summarizing the discussion @Shuyi. I think we need to
>> include
>>>> the "table update mode" problem as it might not be changed easily in
>> the
>>>> future. Regarding "support row/map/array data type", I don't see a
>>>> problem why we should not support them now as the data types are
>> already
>>>> included in the runtime. The "support custom timestamp extractor" is
>>>> solved by the computed columns approach. The "custom watermark
>> strategy"
>>>> can be added by supplying a class name as paramter in my opinion.
>>>>
>>>> Regarding the comments of Lin and Jark:
>>>>
>>>> @Lin: Instantiating a TableSource/Sink should not cost much, but we
>>>> should not mix catalog discussion and DDL at this point.
>>>>
>>>> 4) Event-Time Attributes and Watermarks
>>>> 4.b) Regarding `ts AS SYSTEMROWTIME()` and Lin's comment about "will
>>>> violate the rule": there is no explicit rule of doing so. Computed
>>>> column are also not standard compliant, if we can use information that
>>>> is encoded in constraints we should use it. Adding more and more
>>>> top-level properties makes the interaction with connectors more
>>>> difficult. An additional HEADER keyword sounds too connector-specific
>>>> and also not SQL compliant to me.
>>>>
>>>> 3) SOURCE / SINK / BOTH
>>>> GRANT/INVOKE are mutating an existing table, right? In my opinion,
>>>> independent of SQL databases but focusing on Flink user requirements, a
>>>> CREATE TABLE statement should be an immutable definition of a
>> connection
>>>> to an external system.
>>>>
>>>> 7) Table Update Mode
>>>> As far as I can see, the only thing missing for enabling all table
>> modes
>>>> is the declaration of a change flag. We could introduce a new keyword
>>>> here similar to WATERMARK:
>>>>
>>>> CREATE TABLE output_kafka_t1(
>>>>     id bigint,
>>>>     msg varchar,
>>>>     CHANGE_FLAG FOR isRetraction
>>>> ) WITH (
>>>>     type=kafka
>>>>     ,...
>>>> );
>>>>
>>>> CREATE TABLE output_kafka_t1(
>>>>     CHANGE_FLAG FOR isUpsert
>>>>     id bigint,
>>>>     msg varchar,
>>>>     PRIMARY_KEY(id)
>>>> ) WITH (
>>>>     type=kafka
>>>>     ,...
>>>> );
>>>>
>>>> What do you think?
>>>>
>>>> @Jark: We should definitely stage the discussions and mention the
>>>> opinions and advantages/disadvantages that have been proposed already
>> in
>>>> the FLIP.
>>>>
>>>> Regards,
>>>> Timo
>>>>
>>>> Am 10.12.18 um 08:10 schrieb Jark Wu:
>>>>> Hi all,
>>>>>
>>>>> It's great to see we have an agreement on MVP.
>>>>>
>>>>> 4.b) Ingesting and writing timestamps to systems.
>>>>> I would treat the field as a physical column not a virtual column. If
>>> we
>>>>> treat it as computed column, it will be confused that the behavior is
>>>>> different when it is a source or sink.
>>>>> When it is a physical column, the behavior could be unified. Then the
>>>>> problem is how to mapping from the field to kafka message timestamp?
>>>>> One is Lin proposed above and is also used in KSQL[1]. Another idea
>> is
>>>>> introducing a HEADER column which strictly map by name to the fields
>> in
>>>>> message header.
>>>>> For example,
>>>>>
>>>>> CREATE TABLE output_kafka_t1(
>>>>>     id bigint,
>>>>>     ts timestamp HEADER,
>>>>>     msg varchar
>>>>> ) WITH (
>>>>>     type=kafka
>>>>>     ,...
>>>>> );
>>>>>
>>>>> This is used in Alibaba but not included in the DDL draft. It will
>>>> further
>>>>> extend the SQL syntax, which is we should be cautious about. What do
>>> you
>>>>> think about this two solutions?
>>>>>
>>>>> 4.d) Custom watermark strategies:
>>>>> @Timo,  I don't have a strong opinion on this.
>>>>>
>>>>> 3) SOURCE/SINK/BOTH
>>>>> Agree with Lin, GRANT/INVOKE [SELECT|UPDATE] ON TABLE is a clean and
>>>>> standard way to manage the permission, which is also adopted by
>> HIVE[2]
>>>> and
>>>>> many databases.
>>>>>
>>>>> [1]:
>>> https://docs.confluent.io/current/ksql/docs/tutorials/examples.html
>>>>> [2]:
>>>>>
>> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=45876173#Hivedeprecatedauthorizationmode/LegacyMode-Grant/RevokePrivileges
>>>>> @Timo, it's great if someone can conclude the discussion and
>> summarize
>>>> into
>>>>> a FLIP.
>>>>> @Shuyi, Thanks a lot for putting it all together. The google doc
>> looks
>>>> good
>>>>> to me, and I left some minor comments there.
>>>>>
>>>>> Regarding to the FLIP, I have some suggestions:
>>>>> 1. The FLIP can contain MILESTONE1 and FUTURE WORKS.
>>>>> 2. The MILESTONE1 is the MVP. It describes the MVP DDL syntax.
>>>>> 3. Separate FUTURE WORKS into two parts: UNDER DISCUSSION and
>> ADOPTED.
>>> We
>>>>> can derive MILESTONE2 from this easily when it is ready.
>>>>>
>>>>> I summarized the Future Works based on Shuyi's work:
>>>>>
>>>>> Adopted: (Should detailed described here...)
>>>>> 1. support data type nullability and precision.
>>>>> 2. comment on table and columns.
>>>>>
>>>>> Under Discussion: (Should briefly describe some options...)
>>>>> 1. Ingesting and writing timestamps to systems.
>>>>> 2. support custom watermark strategy.
>>>>> 3. support table update mode
>>>>> 4. support row/map/array data type
>>>>> 5. support schema derivation
>>>>> 6. support system versioned temporal table
>>>>> 7. support table index
>>>>>
>>>>> We can continue the further discussion here, also can separate to an
>>>> other
>>>>> DISCUSS topic if it is a sophisticated problem such as Table Update
>>> Mode,
>>>>> Temporal Table.
>>>>>
>>>>> Best,
>>>>> Jark
>>>>>
>>>>> On Mon, 10 Dec 2018 at 11:54, Lin Li <[hidden email]> wrote:
>>>>>
>>>>>> hi all,
>>>>>> Thanks for your valuable input!
>>>>>>
>>>>>> 4) Event-Time Attributes and Watermarks:
>>>>>> 4.b) @Fabian As you mentioned using a computed columns `ts AS
>>>>>> SYSTEMROWTIME()`
>>>>>> for writing out to kafka table sink will violate the rule that
>>> computed
>>>>>> fields are not emitted.
>>>>>> Since the timestamp column in kafka's header area is a specific
>>>>>> materialization protocol,
>>>>>> why don't we treat it as an connector property? For an example:
>>>>>> ```
>>>>>> CREATE TABLE output_kafka_t1(
>>>>>>     id bigint,
>>>>>>     ts timestamp,
>>>>>>     msg varchar
>>>>>> ) WITH (
>>>>>>     type=kafka,
>>>>>>     header.timestamp=ts
>>>>>>     ,...
>>>>>> );
>>>>>> ```
>>>>>>
>>>>>> 4d) For custom watermark strategies
>>>>>> @Fabian Agree with you that opening another topic about this feature
>>>> later.
>>>>>> 3) SOURCE / SINK / BOTH
>>>>>> I think the permissions and availabilities are two separately
>> things,
>>>>>> permissions
>>>>>> can be managed well by using GRANT/INVOKE(you can call it DCL)
>>> solutions
>>>>>> which
>>>>>> commonly used in different DBs. The permission part can be an new
>>> topic
>>>> for
>>>>>> later discussion, what do you think?
>>>>>>
>>>>>> For the availabilities, @Fabian @Timo  I've another question,
>>>>>> does instantiate a TableSource/Sink cost much or has some other
>>>> downsides?
>>>>>> IMO, create a new source/sink object via the construct seems not
>>> costly.
>>>>>> When receiving a DDL we should associate it with the catalog object
>>>>>> (reusing an existence or create a new one).
>>>>>> Am I lost something important?
>>>>>>
>>>>>> 5. Schema declaration:
>>>>>> @Timo  yes, your concern about the user convenience is very
>> important.
>>>> But
>>>>>> I haven't seen a clear way to solve this so far.
>>>>>> Do we put it later and wait for more inputs from the community?
>>>>>>
>>>>>> Shuyi Chen <[hidden email]> 于2018年12月8日周六 下午4:27写道：
>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> Thanks a lot for the great discussion. I think we can continue the
>>>>>>> discussion here while carving out a MVP so that the community can
>>> start
>>>>>>> working on. Based on the discussion so far, I try to summarize what
>>> we
>>>>>> will
>>>>>>> do for the MVP:
>>>>>>>
>>>>>>> MVP
>>>>>>>
>>>>>>>      1. support CREATE TABLE
>>>>>>>      2. support exisiting data type in Flink SQL, ignore nullability
>>> and
>>>>>>>      precision
>>>>>>>      3. support table comments and column comments
>>>>>>>      4. support table constraint PRIMARY KEY and UNIQUE
>>>>>>>      5. support table properties using key-value pairs
>>>>>>>      6. support partitioned by
>>>>>>>      7. support computed column
>>>>>>>      8. support from-field and from-source timestamp extractors
>>>>>>>      9. support PERIODIC-ASCENDING, PERIODIC-BOUNDED, FROM-SOURCE
>>>> watermark
>>>>>>>      strategies.
>>>>>>>      10. support a table property to allow explicit enforcement of
>>>>>>>      read/write(source/sink) permission of a table
>>>>>>>
>>>>>>> I try to put up the DDL grammar (
>>>>>>>
>>>>>>>
>> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit?usp=sharing
>>>>>>> )
>>>>>>> based on the MVP features above and the previous design docs.
>> Please
>>>>>> take a
>>>>>>> look and comment on it.
>>>>>>>
>>>>>>>
>>>>>>> Also, I summarize the future Improvement on CREATE TABLE as the
>>>>>> followings:
>>>>>>>      1. support table update mode
>>>>>>>      2. support data type nullability and precision
>>>>>>>      3. support row/map/array data type
>>>>>>>      4. support custom timestamp extractor and watermark strategy
>>>>>>>      5. support schema derivation
>>>>>>>      6. support system versioned temporal table
>>>>>>>      7. support table index
>>>>>>>
>>>>>>> I suggest we first agree on the MVP feature list and the MVP
>> grammar.
>>>> And
>>>>>>> then we can either continue the discussion of the future
>> improvements
>>>>>> here,
>>>>>>> or create separate JIRAs for each item and discuss further in the
>>> JIRA.
>>>>>>> What do you guys think?
>>>>>>>
>>>>>>> Shuyi
>>>>>>>
>>>>>>> On Fri, Dec 7, 2018 at 7:54 AM Timo Walther <[hidden email]>
>>>> wrote:
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> I think we are making good progress. Thanks for all the feedback
>> so
>>>>>> far.
>>>>>>>> 3. Sources/Sinks:
>>>>>>>> It seems that I can not find supporters for explicit SOURCE/SINK
>>>>>>>> declaration so I'm fine with not using those keywords.
>>>>>>>> @Fabian: Maybe we don't haven have to change the TableFactory
>>>> interface
>>>>>>>> but just provide some helper functions in the TableFactoryService.
>>>> This
>>>>>>>> would solve the availability problem, but the permission problem
>>> would
>>>>>>>> still not be solved. If you are fine with it, we could introduce a
>>>>>>>> property instead?
>>>>>>>>
>>>>>>>> 5. Schema declaration:
>>>>>>>> @Lin: We should find an agreement on this as it requires changes
>> to
>>>> the
>>>>>>>> TableFactory interface. We should minimize changes to this
>> interface
>>>>>>>> because it is user-facing. Especially, if format schema and table
>>>>>> schema
>>>>>>>> differ, the need for such a functionality is very important. Our
>>> goal
>>>>>> is
>>>>>>>> to connect to existing infrastructure. For example, if we are
>> using
>>>>>> Avro
>>>>>>>> and the existing Avro format has enums but Flink SQL does not
>>> support
>>>>>>>> enums, it would be helpful to let the Avro format derive a table
>>>>>> schema.
>>>>>>>> Otherwise your need to declare both schemas which leads to CREATE
>>>> TABLE
>>>>>>>> statements of 400 lines+.
>>>>>>>> I think the mentioned query:
>>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
>>>>>>>> format.schema-file = "/my/avrofile.avsc")
>>>>>>>> is fine and should only be valid if the schema contains no
>>>> non-computed
>>>>>>>> columns.
>>>>>>>>
>>>>>>>> 7. Table Update Mode:
>>>>>>>> After thinking about it again, I agree. The mode of the sinks can
>> be
>>>>>>>> derived from the query and the existence of a PRIMARY KEY
>>> declaration.
>>>>>>>> But Fabian raised a very good point. How do we deal with sources?
>>>> Shall
>>>>>>>> we introduce a new keywords similar to WATERMARKS such that a
>>>>>>>> upsert/retract flag is not part of the visible schema?
>>>>>>>>
>>>>>>>> 4a. How to mark a field as attribute?
>>>>>>>> @Jark: Thanks for the explanation of the WATERMARK clause
>> semantics.
>>>>>>>> This is a nice way of marking existing fields. This sounds good to
>>> me.
>>>>>>>> 4c) WATERMARK as constraint
>>>>>>>> I'm fine with leaving the WATERMARK clause in the schema
>> definition.
>>>>>>>> 4d) Custom watermark strategies:
>>>>>>>> I would already think about custom watermark strategies as the
>>> current
>>>>>>>> descriptor design already supports this. ScalarFunction's don't
>> work
>>>> as
>>>>>>>> a PeriodicWatermarkAssigner has different semantics. Why not
>> simply
>>>>>>>> entering the a full class name here as it is done in the current
>>>>>> design?
>>>>>>>> 4.b) Ingesting and writing timestamps to systems (like Kafka)
>>>>>>>> @Fabian: Yes, your suggestion sounds good to me. This behavior
>> would
>>>> be
>>>>>>>> similar to our current `timestamps: from-source` design.
>>>>>>>>
>>>>>>>> Once our discussion has found a conclusion, I would like to
>>> volunteer
>>>>>>>> and summarize the outcome of this mailing thread. It nicely aligns
>>>> with
>>>>>>>> the update work on the connector improvements document (that I
>>> wanted
>>>>>> to
>>>>>>>> do anyway) and the ongoing external catalog discussion.
>>> Furthermore, I
>>>>>>>> would also want to propose how to change existing interfaces by
>>>> keeping
>>>>>>>> the DDL, connector improvements, and external catalog support in
>>> mind.
>>>>>>>> Would that be ok for you?
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Timo
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Am 07.12.18 um 14:48 schrieb Fabian Hueske:
>>>>>>>>> Hi all,
>>>>>>>>>
>>>>>>>>> Thanks for the discussion.
>>>>>>>>> I'd like to share my point of view as well.
>>>>>>>>>
>>>>>>>>> 4) Event-Time Attributes and Watermarks:
>>>>>>>>> 4.a) I agree with Lin and Jark's proposal. Declaring a watermark
>> on
>>>>>> an
>>>>>>>>> attribute declares it as an event-time attribute.
>>>>>>>>> 4.b) Ingesting and writing timestamps to systems (like Kafka). We
>>>>>> could
>>>>>>>> use
>>>>>>>>> a special function like (ts AS SYSTEMROWTIME()). This function
>> will
>>>>>>>>> indicate that we read the timestamp directly from the system (and
>>> not
>>>>>>> the
>>>>>>>>> data). We can also write the field back to the system when
>> emitting
>>>>>> the
>>>>>>>>> table (violating the rule that computed fields are not emitted).
>>>>>>>>> 4c) I would treat WATERMARK similar to a PRIMARY KEY or UNIQUE
>> KEY
>>>>>>>>> constraint and therefore keep it in the schema definition.
>>>>>>>>> 4d) For custom watermark strategies, a simple expressions or
>>>>>>>>> ScalarFunctions won't be sufficient. Sophisticated approaches
>> could
>>>>>>>> collect
>>>>>>>>> histograms, etc. But I think we can leave that out for later.
>>>>>>>>>
>>>>>>>>> 3) SOURCE / SINK / BOTH
>>>>>>>>> As you said, there are two things to consider here: permission
>> and
>>>>>>>>> availability of a TableSource/TableSink.
>>>>>>>>> I think that neither should be a reason to add a keyword at such
>> a
>>>>>>>>> sensitive position.
>>>>>>>>> However, I also see Timo's point that it would be good to know
>>>>>> up-front
>>>>>>>> how
>>>>>>>>> a table can be used without trying to instantiate a
>>> TableSource/Sink
>>>>>>> for
>>>>>>>> a
>>>>>>>>> query.
>>>>>>>>> Maybe we can extend the TableFactory such that it provides
>>>>>> information
>>>>>>>>> about which sources/sinks it can provide.
>>>>>>>>>
>>>>>>>>> 7. Table Update Mode
>>>>>>>>> Something that we definitely need to consider is how tables are
>>>>>>> ingested,
>>>>>>>>> i.e., append, retract or upsert.
>>>>>>>>> Especially, since upsert and retraction need a meta-data column
>>> that
>>>>>>>>> indicates whether an event is an insert (or upsert) or a delete
>>>>>> change.
>>>>>>>>> This column needs to be identified somehow, most likely as part
>> of
>>>>>> the
>>>>>>>>> input format. Ideally, this column should not be part of the
>> table
>>>>>>> schema
>>>>>>>>> (as it would be always true).
>>>>>>>>> Emitting tables is not so much of an issue as the properties of
>> the
>>>>>>> table
>>>>>>>>> tell use what to do (append-only/update, unique key y/n).
>>>>>>>>>
>>>>>>>>> Best,
>>>>>>>>> Fabian
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Am Fr., 7. Dez. 2018 um 10:39 Uhr schrieb Jark Wu <
>>> [hidden email]
>>>>>>> :
>>>>>>>>>> Hi Timo,
>>>>>>>>>>
>>>>>>>>>> Thanks for your quickly feedback! Here are some of my thoughts:
>>>>>>>>>>
>>>>>>>>>> Append, upserts, retract mode on sinks is also a very complex
>>>>>>> problem. I
>>>>>>>>>> think append/upserts/retract is the ability of a table, user do
>>> not
>>>>>>>> need to
>>>>>>>>>> specify a table is used for append or retraction or upsert. The
>>>>>> query
>>>>>>>> can
>>>>>>>>>> choose which mode the sink is. If an unbounded groupby is
>> inserted
>>>>>>> into
>>>>>>>> an
>>>>>>>>>> append sink (the sink only implements/supports append), an
>>> exception
>>>>>>>> can be
>>>>>>>>>> thrown. A more complex problem is, if we want to write
>>>>>>>> retractions/upserts
>>>>>>>>>> to Kafka, how to encode the change flag (add or retract/delete)
>> on
>>>>>> the
>>>>>>>>>> table? Maybe we should propose some protocal for the change flag
>>>>>>>> encoding,
>>>>>>>>>> but I don't have a clear idea about this right now.
>>>>>>>>>>
>>>>>>>>>> 3. Sources/Sinks: The source/sink tag is similar to the
>>>>>>>>>> append/upsert/retract problem. Besides source/sink, actully we
>>> have
>>>>>>>> stream
>>>>>>>>>> source, stream sink, batch source, batch sink, and the stream
>> sink
>>>>>>> also
>>>>>>>>>> include append/upsert/retract three modes. Should we put all the
>>>>>> tags
>>>>>>> on
>>>>>>>>>> the CREATE TABLE? IMO, the table's ability is defined by the
>> table
>>>>>>>> itself,
>>>>>>>>>> user do not need to specify it. If it is only a readable table,
>> an
>>>>>>>>>> exception can be thrown when write to it. As the source/sink tag
>>> can
>>>>>>> be
>>>>>>>>>> omitted in CREATE TABLE, could we skip it and only support
>> CREATE
>>>>>>> TABLE
>>>>>>>> in
>>>>>>>>>> the first version, and add it back in the future when we really
>>> need
>>>>>>>> it? It
>>>>>>>>>> keeps API compatible and make sure the MVP is what we consider
>>>>>>> clearly.
>>>>>>>>>> 4a. How to mark a field as attribute?
>>>>>>>>>> The watermark definition includes two parts: use which field as
>>> time
>>>>>>>>>> attribute and use what generate strategy.
>>>>>>>>>> When we want to mark `ts` field as attribute: WATERMARK FOR `ts`
>>> AS
>>>>>>>> OFFSET
>>>>>>>>>> '5' SECOND.
>>>>>>>>>> If we have a POJO{id, user, ts} field named "pojo", we can mark
>> it
>>>>>>> like
>>>>>>>>>> this: WATERMARK FOR pojo.ts AS OFFSET '5' SECOND
>>>>>>>>>>
>>>>>>>>>> 4b. timestamp write to Kafka message header
>>>>>>>>>> Even though we can define multiple time attribute on a table,
>> only
>>>>>> one
>>>>>>>> time
>>>>>>>>>> attribute can be actived/used in a query (in a stream). When we
>>>>>> enable
>>>>>>>>>> `writeTiemstamp`, the only attribute actived in the stream will
>> be
>>>>>>>> write to
>>>>>>>>>> Kafka message header. What I mean the timestmap in StreamRecord
>> is
>>>>>> the
>>>>>>>> time
>>>>>>>>>> attribute in the stream.
>>>>>>>>>>
>>>>>>>>>> 4c. Yes. We introduced the WATERMARK keyword similar to the
>> INDEX,
>>>>>>>> PRIMARY
>>>>>>>>>> KEY keywords.
>>>>>>>>>>
>>>>>>>>>> @Timo, Do you have any other advice or questions on the
>> watermark
>>>>>>>> syntax ?
>>>>>>>>>> For example, the builtin strategy name: "BOUNDED WITH OFFSET" VS
>>>>>>>> "OFFSET"
>>>>>>>>>> VS ...
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Cheers,
>>>>>>>>>> Jark
>>>>>>>>>>
>>>>>>>>>> On Fri, 7 Dec 2018 at 17:13, Lin Li <[hidden email]>
>>> wrote:
>>>>>>>>>>> Hi Timo,
>>>>>>>>>>> Thanks for your feedback, here's some thoughts of mine:
>>>>>>>>>>>
>>>>>>>>>>> 3. Sources/Sinks:
>>>>>>>>>>> "Let's assume an interactive CLI session, people should be able
>>> to
>>>>>>> list
>>>>>>>>>> all
>>>>>>>>>>> source table and sink tables to know upfront if they can use an
>>>>>>> INSERT
>>>>>>>>>> INTO
>>>>>>>>>>> here or not."
>>>>>>>>>>> This requirement can be simply resolved by a document that list
>>> all
>>>>>>>>>>> supported source/sink/both connectors and the sql-client can
>>>>>> perform
>>>>>>> a
>>>>>>>>>>> quick check. It's only an implementation choice, not necessary
>>> for
>>>>>>> the
>>>>>>>>>>> syntax.
>>>>>>>>>>> For connector implementation, a connector may implement one or
>>> some
>>>>>>> or
>>>>>>>>>> all
>>>>>>>>>>> of the [Stream|Batch]Source/[Stream|Batch]Sink traits, we can
>>>>>> derive
>>>>>>>> the
>>>>>>>>>>> availability for any give query without the SOURCE/SINk
>> keywords
>>> or
>>>>>>>>>>> specific table properties in WITH clause.
>>>>>>>>>>> Since there's still indeterminacy, shall we skip these two
>>> keywords
>>>>>>> for
>>>>>>>>>> the
>>>>>>>>>>> MVP DDL? We can make further discussion after users' feedback.
>>>>>>>>>>>
>>>>>>>>>>> 6. Partitioning and keys
>>>>>>>>>>> Agree with you that raise the priority of table constraint and
>>>>>>>>>> partitioned
>>>>>>>>>>> table support for better connectivity to Hive and Kafka. I'll
>> add
>>>>>>>>>>> partitioned table syntax(compatible to hive) into the DDL Draft
>>> doc
>>>>>>>>>>> later[1].
>>>>>>>>>>>
>>>>>>>>>>> 5. Schema declaration
>>>>>>>>>>> "if users want to declare computed columns they have a "schema"
>>>>>>>>>> constraints
>>>>>>>>>>> but without columns
>>>>>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
>>>>>>>>>>> format.schema-file = "/my/avrofile.avsc") "
>>>>>>>>>>>
>>>>>>>>>>>    From the point of my view, this ddl is invalid because the
>>>> primary
>>>>>>> key
>>>>>>>>>>> constraint already references two columns but types unseen.
>>>>>>>>>>> And Xuefu pointed a important matching problem, so let's put
>>> schema
>>>>>>>>>>> derivation as a follow-up extension ?
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Timo Walther <[hidden email]> 于2018年12月6日周四 下午6:05写道：
>>>>>>>>>>>
>>>>>>>>>>>> Hi everyone,
>>>>>>>>>>>>
>>>>>>>>>>>> great to have such a lively discussion. My next batch of
>>> feedback:
>>>>>>>>>>>> @Jark: We don't need to align the descriptor approach with
>> SQL.
>>>>>> I'm
>>>>>>>>>> open
>>>>>>>>>>>> for different approaches as long as we can serve a broad set
>> of
>>>>>> use
>>>>>>>>>>>> cases and systems. The descriptor approach was a first attempt
>>> to
>>>>>>>> cover
>>>>>>>>>>>> all aspects and connector/format characteristics. Just another
>>>>>>>> example,
>>>>>>>>>>>> that is missing in the DDL design: How can a user decide if
>>>>>> append,
>>>>>>>>>>>> retraction, or upserts should be used to sink data into the
>>> target
>>>>>>>>>>>> system? Do we want to define all these improtant properties in
>>> the
>>>>>>> big
>>>>>>>>>>>> WITH property map? If yes, we are already close to the
>>> descriptor
>>>>>>>>>>>> approach. Regarding the "standard way", most DDL languages
>> have
>>>>>> very
>>>>>>>>>>>> custom syntax so there is not a real "standard".
>>>>>>>>>>>>
>>>>>>>>>>>> 3. Sources/Sinks: @Lin: If a table has both read/write access
>> it
>>>>>> can
>>>>>>>> be
>>>>>>>>>>>> created using a regular CREATE TABLE (omitting a specific
>>>>>>> source/sink)
>>>>>>>>>>>> declaration. Regarding the transition from source/sink to
>> both,
>>>>>> yes
>>>>>>> we
>>>>>>>>>>>> would need to update the a DDL and catalogs. But is this a
>>>>>> problem?
>>>>>>>> One
>>>>>>>>>>>> also needs to add new queries that use the tables. @Xuefu: It
>> is
>>>>>> not
>>>>>>>>>>>> only about security aspects. Especially for streaming use
>> cases,
>>>>>> not
>>>>>>>>>>>> every connector can be used as a source easily. For example, a
>>>>>> JDBC
>>>>>>>>>> sink
>>>>>>>>>>>> is easier than a JDBC source. Let's assume an interactive CLI
>>>>>>> session,
>>>>>>>>>>>> people should be able to list all source table and sink tables
>>> to
>>>>>>> know
>>>>>>>>>>>> upfront if they can use an INSERT INTO here or not.
>>>>>>>>>>>>
>>>>>>>>>>>> 6. Partitioning and keys: @Lin: I would like to include this
>> in
>>>>>> the
>>>>>>>>>>>> design given that Hive integration and Kafka key support are
>> in
>>>>>> the
>>>>>>>>>>>> making/are on our roadmap for this release.
>>>>>>>>>>>>
>>>>>>>>>>>> 5. Schema declaration: @Lin: You are right it is not
>>> conflicting.
>>>>>> I
>>>>>>>>>> just
>>>>>>>>>>>> wanted to raise the point because if users want to declare
>>>>>> computed
>>>>>>>>>>>> columns they have a "schema" constraints but without columns.
>>> Are
>>>>>> we
>>>>>>>> ok
>>>>>>>>>>>> with a syntax like ...
>>>>>>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
>>>>>>>>>>>> format.schema-file = "/my/avrofile.avsc") ?
>>>>>>>>>>>> @Xuefu: Yes, you are right that an external schema might not
>>>>>> excatly
>>>>>>>>>>>> match but this is true for both directions:
>>>>>>>>>>>> table schema "derives" format schema and format schema
>> "derives"
>>>>>>> table
>>>>>>>>>>>> schema.
>>>>>>>>>>>>
>>>>>>>>>>>> 7. Hive compatibility: @Xuefu: I agree that Hive is popular
>> but
>>> we
>>>>>>>>>>>> should not just adopt everything from Hive as there syntax is
>>> very
>>>>>>>>>>>> batch-specific. We should come up with a superset of
>> historical
>>>>>> and
>>>>>>>>>>>> future requirements. Supporting Hive queries can be an
>>>>>> intermediate
>>>>>>>>>>>> layer on top of Flink's DDL.
>>>>>>>>>>>>
>>>>>>>>>>>> 4. Time attributes: @Lin: I'm fine with changing the
>>>>>>>> TimestampExtractor
>>>>>>>>>>>> interface as this is also important for better separation of
>>>>>>> connector
>>>>>>>>>>>> and table module [1]. However, I'm wondering about watermark
>>>>>>>>>> generation.
>>>>>>>>>>>> 4a. timestamps are in the schema twice:
>>>>>>>>>>>> @Jark: "existing field is Long/Timestamp, we can just use it
>> as
>>>>>>>>>>>> rowtime": yes, but we need to mark a field as such an
>> attribute.
>>>>>> How
>>>>>>>>>>>> does the syntax for marking look like? Also in case of
>>> timestamps
>>>>>>> that
>>>>>>>>>>>> are nested in the schema?
>>>>>>>>>>>>
>>>>>>>>>>>> 4b. how can we write out a timestamp into the message header?:
>>>>>>>>>>>> I agree to simply ignore computed columns when writing out.
>> This
>>>>>> is
>>>>>>>>>> like
>>>>>>>>>>>> 'field-change: add' that I mentioned in the improvements
>>> document.
>>>>>>>>>>>> @Jark: "then the timestmap in StreamRecord will be write to
>>> Kafka
>>>>>>>>>>>> message header": Unfortunately, there is no timestamp in the
>>>>>> stream
>>>>>>>>>>>> record. Additionally, multiple time attributes can be in a
>>> schema.
>>>>>>> So
>>>>>>>>>> we
>>>>>>>>>>>> need a constraint that tells the sink which column to use
>>>>>> (possibly
>>>>>>>>>>>> computed as well)?
>>>>>>>>>>>>
>>>>>>>>>>>> 4c. separate all time attribute concerns into a special clause
>>>>>> next
>>>>>>> to
>>>>>>>>>>>> the regular schema?
>>>>>>>>>>>> @Jark: I don't have a strong opinion on this. I just have the
>>>>>>> feeling
>>>>>>>>>>>> that the "schema part" becomes quite messy because the actual
>>>>>> schema
>>>>>>>>>>>> with types and fields is accompanied by so much metadata about
>>>>>>>>>>>> timestamps, watermarks, keys,... and we would need to
>> introduce
>>> a
>>>>>>> new
>>>>>>>>>>>> WATERMARK keyword within a schema that was close to standard
>> up
>>> to
>>>>>>>> this
>>>>>>>>>>>> point.
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks everyone,
>>>>>>>>>>>> Timo
>>>>>>>>>>>>
>>>>>>>>>>>> [1] https://issues.apache.org/jira/browse/FLINK-9461
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Am 06.12.18 um 07:08 schrieb Jark Wu:
>>>>>>>>>>>>> Hi Timo,
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thank you for the valuable feedbacks.
>>>>>>>>>>>>>
>>>>>>>>>>>>> First of all, I think we don't need to align the SQL
>>>>>> functionality
>>>>>>> to
>>>>>>>>>>>>> Descriptor. Because SQL is a more standard API, we should be
>> as
>>>>>>>>>>> cautious
>>>>>>>>>>>> as
>>>>>>>>>>>>> possible to extend the SQL syntax. If something can be done
>> in
>>> a
>>>>>>>>>>> standard
>>>>>>>>>>>>> way, we shouldn't introduce something new.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Here are some of my thoughts:
>>>>>>>>>>>>>
>>>>>>>>>>>>> 1. Scope: Agree.
>>>>>>>>>>>>> 2. Constraints: Agree.
>>>>>>>>>>>>> 4. Time attributes:
>>>>>>>>>>>>>       4a. timestamps are in the schema twice.
>>>>>>>>>>>>>        If an existing field is Long/Timestamp, we can just use
>>> it
>>>>>> as
>>>>>>>>>>>> rowtime,
>>>>>>>>>>>>> no twice defined. If it is not a Long/Timestamp, we use
>>> computed
>>>>>>>>>> column
>>>>>>>>>>>> to
>>>>>>>>>>>>> get an expected timestamp column to be rowtime, is this what
>>> you
>>>>>>> mean
>>>>>>>>>>>>> defined twice?  But I don't think it is a problem, but an
>>>>>>> advantages,
>>>>>>>>>>>>> because it is easy to use, user do not need to consider
>> whether
>>>>>> to
>>>>>>>>>>>> "replace
>>>>>>>>>>>>> the existing column" or "add a new column", he will not be
>>>>>> confused
>>>>>>>>>>>> what's
>>>>>>>>>>>>> the real schema is, what's the index of rowtime in the
>> schema?
>>>>>>>>>>> Regarding
>>>>>>>>>>>> to
>>>>>>>>>>>>> the optimization, even if timestamps are in schema twice,
>> when
>>>>>> the
>>>>>>>>>>>> original
>>>>>>>>>>>>> timestamp is never used in query, then the projection
>> pushdown
>>>>>>>>>>>> optimization
>>>>>>>>>>>>> can cut this field as early as possible, which is exactly the
>>>>>> same
>>>>>>> as
>>>>>>>>>>>>> "replacing the existing column" in runtime.
>>>>>>>>>>>>>
>>>>>>>>>>>>>        4b. how can we write out a timestamp into the message
>>>>>> header?
>>>>>>>>>>>>>         That's a good point. I think computed column is just a
>>>>>>> virtual
>>>>>>>>>>>> column
>>>>>>>>>>>>> on table which is only relative to reading. If we want to
>> write
>>>>>> to
>>>>>>> a
>>>>>>>>>>>> table
>>>>>>>>>>>>> with computed column defined, we only need to provide the
>>> columns
>>>>>>>>>>> except
>>>>>>>>>>>>> computed columns (see SQL Server [1]). The computed column is
>>>>>>> ignored
>>>>>>>>>>> in
>>>>>>>>>>>>> the insert statement. Get back to the question, how can we
>>> write
>>>>>>> out
>>>>>>>>>> a
>>>>>>>>>>>>> timestamp into the message header? IMO, we can provide a
>>>>>>>>>> configuration
>>>>>>>>>>> to
>>>>>>>>>>>>> support this, such as `kafka.writeTimestamp=true`, then the
>>>>>>> timestmap
>>>>>>>>>>> in
>>>>>>>>>>>>> StreamRecord will be write to Kafka message header. What do
>> you
>>>>>>>>>> think?
>>>>>>>>>>>>>         4c. separate all time attribute concerns into a
>> special
>>>>>>> clause
>>>>>>>>>>> next
>>>>>>>>>>>> to
>>>>>>>>>>>>> the regular schema?
>>>>>>>>>>>>>         Separating watermark into a special clause similar to
>>>>>>>>>> PARTITIONED
>>>>>>>>>>>> BY is
>>>>>>>>>>>>> also a good idea. Conceptually, it's fine to put watermark in
>>>>>>> schema
>>>>>>>>>>> part
>>>>>>>>>>>>> or out schema part. But if we want to support multiple
>>> watermark
>>>>>>>>>>>>> definition, maybe it would be better to put it in schema
>> part.
>>> It
>>>>>>> is
>>>>>>>>>>>>> similar to Index Definition that we can define several
>> indexes
>>>>>> on a
>>>>>>>>>>> table
>>>>>>>>>>>>> in schema part.
>>>>>>>>>>>>>
>>>>>>>>>>>>>         4d. How can people come up with a custom watermark
>>>>>> strategy?
>>>>>>>>>>>>>         In most cases, the built-in strategy can works good.
>> If
>>> we
>>>>>>> need
>>>>>>>>>> a
>>>>>>>>>>>>> custom one, we can use a scalar function which restrict to
>> only
>>>>>>>>>> return
>>>>>>>>>>> a
>>>>>>>>>>>>> nullable Long, and use it in SQL like: WATERMARK for rowtime
>> AS
>>>>>>>>>>>>> watermarkUdf(a, b, c). The `watermarkUdf` is a user-defined
>>>>>> scalar
>>>>>>>>>>>> function
>>>>>>>>>>>>> accepts 3 parameters and return a nullable Long which can be
>>> used
>>>>>>> as
>>>>>>>>>>>>> punctuated watermark assigner. Another choice is
>> implementing a
>>>>>>> class
>>>>>>>>>>>>> extending the
>>>>>>>>>>>>>
>> `org.apache.flink.table.sources.wmstrategies.WatermarkStrategy`
>>>>>> and
>>>>>>>>>> use
>>>>>>>>>>>> it
>>>>>>>>>>>>> in SQL: WATERMARK for rowtime AS
>> 'com.my.MyWatermarkStrategy'.
>>>>>> But
>>>>>>> if
>>>>>>>>>>>>> scalar function can cover the requirements here, I would
>> prefer
>>>>>> it
>>>>>>>>>>> here,
>>>>>>>>>>>>> because it keeps standard compliant. BTW, this feature is not
>>> in
>>>>>>> MVP,
>>>>>>>>>>> we
>>>>>>>>>>>>> can discuss it more depth in the future when we need it.
>>>>>>>>>>>>>
>>>>>>>>>>>>> 5. Schema declaration:
>>>>>>>>>>>>> I like the proposal to omit the schema if we can get the
>> schema
>>>>>>> from
>>>>>>>>>>>>> external storage or something schema file. Actually, we have
>>>>>>> already
>>>>>>>>>>>>> encountered this requirement in out company.
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> +1 to @Xuefu that we should be as close as possible to Hive
>>>>>> syntax
>>>>>>>>>>> while
>>>>>>>>>>>>> keeping SQL ANSI standard. This will make it more acceptable
>>> and
>>>>>>>>>> reduce
>>>>>>>>>>>> the
>>>>>>>>>>>>> learning cost for user.
>>>>>>>>>>>>>
>>>>>>>>>>>>> [1]:
>>>>>>>>>>>>>
>> https://docs.microsoft.com/en-us/sql/relational-databases/partitions/create-partitioned-tables-and-indexes?view=sql-server-2017
>>>>>>>>>>>>> Best,
>>>>>>>>>>>>> Jark
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Thu, 6 Dec 2018 at 12:09, Zhang, Xuefu <
>>>>>> [hidden email]
>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>> Hi Timo/Shuyi/Lin,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thanks for the discussions. It seems that we are converging
>> to
>>>>>>>>>>> something
>>>>>>>>>>>>>> meaningful. Here are some of my thoughts:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 1. +1 on MVP DDL
>>>>>>>>>>>>>> 3. Markers for source or sink seem more about permissions on
>>>>>>> tables
>>>>>>>>>>> that
>>>>>>>>>>>>>> belong to a security component. Unless the table is created
>>>>>>>>>>> differently
>>>>>>>>>>>>>> based on source, sink, or both, it doesn't seem necessary to
>>> use
>>>>>>>>>> these
>>>>>>>>>>>>>> keywords to enforce permissions.
>>>>>>>>>>>>>> 5. It might be okay if schema declaration is always needed.
>>>>>> While
>>>>>>>>>>> there
>>>>>>>>>>>>>> might be some duplication sometimes, it's not always true.
>> For
>>>>>>>>>>> example,
>>>>>>>>>>>>>> external schema may not be exactly matching Flink schema.
>> For
>>>>>>>>>>> instance,
>>>>>>>>>>>>>> data types. Even if so, perfect match is not required. For
>>>>>>> instance,
>>>>>>>>>>> the
>>>>>>>>>>>>>> external schema file may evolve while table schema in Flink
>>> may
>>>>>>> stay
>>>>>>>>>>>>>> unchanged. A responsible reader should be able to scan the
>>> file
>>>>>>>>>> based
>>>>>>>>>>> on
>>>>>>>>>>>>>> file schema and return the data based on table schema.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Other aspects:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 7. Hive compatibility. Since Flink SQL will soon be able to
>>>>>>> operate
>>>>>>>>>> on
>>>>>>>>>>>>>> Hive metadata and data, it's an add-on benefit if we can be
>>>>>>>>>> compatible
>>>>>>>>>>>> with
>>>>>>>>>>>>>> Hive syntax/semantics while following ANSI standard. At
>> least
>>> we
>>>>>>>>>>> should
>>>>>>>>>>>> be
>>>>>>>>>>>>>> as close as possible. Hive DDL can found at
>>>>>>>>>>>>>>
>> https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL
>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>> Xuefu
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>> ------------------------------------------------------------------
>>>>>>>>>>>>>> Sender:Lin Li <[hidden email]>
>>>>>>>>>>>>>> Sent at:2018 Dec 6 (Thu) 10:49
>>>>>>>>>>>>>> Recipient:dev <[hidden email]>
>>>>>>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Hi Timo and Shuyi,
>>>>>>>>>>>>>>       thanks for your feedback.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 1. Scope
>>>>>>>>>>>>>> agree with you we should focus on the MVP DDL first.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 2. Constraints
>>>>>>>>>>>>>> yes, this can be a follow-up issue.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 3. Sources/Sinks
>>>>>>>>>>>>>> If a TABLE has both read/write access requirements, should
>> we
>>>>>>>>>> declare
>>>>>>>>>>> it
>>>>>>>>>>>>>> using
>>>>>>>>>>>>>> `CREATE [SOURCE_SINK|BOTH] TABLE tableName ...` ? A further
>>>>>>>>>> question,
>>>>>>>>>>>> if a
>>>>>>>>>>>>>> TABLE
>>>>>>>>>>>>>> t1 firstly declared as read only (as a source table), then
>> for
>>>>>>> some
>>>>>>>>>>> new
>>>>>>>>>>>>>> requirements
>>>>>>>>>>>>>> t1 will change to a sink table,  in this case we need
>> updating
>>>>>>> both
>>>>>>>>>>> the
>>>>>>>>>>>> DDL
>>>>>>>>>>>>>> and catalogs.
>>>>>>>>>>>>>> Further more, let's think about the BATCH query, update one
>>>>>> table
>>>>>>>>>>>> in-place
>>>>>>>>>>>>>> can be a common case.
>>>>>>>>>>>>>> e.g.,
>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>> CREATE TABLE t1 (
>>>>>>>>>>>>>>       col1 varchar,
>>>>>>>>>>>>>>       col2 int,
>>>>>>>>>>>>>>       col3 varchar
>>>>>>>>>>>>>>       ...
>>>>>>>>>>>>>> );
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> INSERT [OVERWRITE] TABLE t1
>>>>>>>>>>>>>> AS
>>>>>>>>>>>>>> SELECT
>>>>>>>>>>>>>>       (some computing ...)
>>>>>>>>>>>>>> FROM t1;
>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>> So, let's forget these SOURCE/SINK keywords in DDL. For the
>>>>>>>>>> validation
>>>>>>>>>>>>>> purpose, we can find out other ways.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 4. Time attributes
>>>>>>>>>>>>>> As Shuyi mentioned before, there exists an
>>>>>>>>>>>>>>
>>> `org.apache.flink.table.sources.tsextractors.TimestampExtractor`
>>>>>>> for
>>>>>>>>>>>> custom
>>>>>>>>>>>>>> defined time attributes usage, but this expression based
>> class
>>>>>> is
>>>>>>>>>> more
>>>>>>>>>>>>>> friendly for table api not the SQL.
>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>> /**
>>>>>>>>>>>>>>       * Provides the an expression to extract the timestamp
>>> for a
>>>>>>>>>> rowtime
>>>>>>>>>>>>>> attribute.
>>>>>>>>>>>>>>       */
>>>>>>>>>>>>>> abstract class TimestampExtractor extends
>> FieldComputer[Long]
>>>>>> with
>>>>>>>>>>>>>> Serializable {
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>       /** Timestamp extractors compute the timestamp as Long.
>>> */
>>>>>>>>>>>>>>       override def getReturnType: TypeInformation[Long] =
>>>>>>>>>>>>>> Types.LONG.asInstanceOf[TypeInformation[Long]]
>>>>>>>>>>>>>> }
>>>>>>>>>>>>>> ```
>>>>>>>>>>>>>> BTW, I think both the Scalar function and the
>>> TimestampExtractor
>>>>>>> are
>>>>>>>>>>>>>> expressing computing logic, the TimestampExtractor has no
>> more
>>>>>>>>>>>> advantage in
>>>>>>>>>>>>>> SQL scenarios.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 6. Partitioning and keys
>>>>>>>>>>>>>> Primary Key is included in Constraint part, and partitioned
>>>>>> table
>>>>>>>>>>>> support
>>>>>>>>>>>>>> can be another topic later.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> 5. Schema declaration
>>>>>>>>>>>>>> Agree with you that we can do better schema derivation for
>>> user
>>>>>>>>>>>>>> convenience, but this is not conflict with the syntax.
>>>>>>>>>>>>>> Table properties can carry any useful informations both for
>>> the
>>>>>>>>>> users
>>>>>>>>>>>> and
>>>>>>>>>>>>>> the framework, I like your `contract name` proposal,
>>>>>>>>>>>>>> e.g., `WITH (format.type = avro)`, the framework can
>> recognize
>>>>>>> some
>>>>>>>>>>>>>> `contract name` like `format.type`, `connector.type` and
>> etc.
>>>>>>>>>>>>>> And also derive the table schema from an existing schema
>> file
>>>>>> can
>>>>>>> be
>>>>>>>>>>>> handy
>>>>>>>>>>>>>> especially one with too many table columns.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Regards,
>>>>>>>>>>>>>> Lin
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Timo Walther <[hidden email]> 于2018年12月5日周三 下午10:40写道：
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Hi Jark and Shuyi,
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> thanks for pushing the DDL efforts forward. I agree that we
>>>>>>> should
>>>>>>>>>>> aim
>>>>>>>>>>>>>>> to combine both Shuyi's design and your design.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Here are a couple of concerns that I think we should
>> address
>>> in
>>>>>>> the
>>>>>>>>>>>>>> design:
>>>>>>>>>>>>>>> 1. Scope: Let's focuses on a MVP DDL for CREATE TABLE
>>>>>> statements
>>>>>>>>>>> first.
>>>>>>>>>>>>>>> I think this topic has already enough potential for long
>>>>>>>>>> discussions
>>>>>>>>>>>> and
>>>>>>>>>>>>>>> is very helpful for users. We can discuss CREATE VIEW and
>>>>>> CREATE
>>>>>>>>>>>>>>> FUNCTION afterwards as they are not related to each other.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 2. Constraints: I think we should consider things like
>>>>>>> nullability,
>>>>>>>>>>>>>>> VARCHAR length, and decimal scale and precision in the
>> future
>>>>>> as
>>>>>>>>>> they
>>>>>>>>>>>>>>> allow for nice optimizations. However, since both the
>>>>>> translation
>>>>>>>>>> and
>>>>>>>>>>>>>>> runtime operators do not support those features. I would
>> not
>>>>>>>>>>> introduce
>>>>>>>>>>>> a
>>>>>>>>>>>>>>> arbitrary default value but omit those parameters for now.
>>> This
>>>>>>> can
>>>>>>>>>>> be
>>>>>>>>>>>> a
>>>>>>>>>>>>>>> follow-up issue once the basic DDL has been merged.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 3. Sources/Sinks: We had a discussion about CREATE TABLE vs
>>>>>>> CREATE
>>>>>>>>>>>>>>> [SOURCE|SINK|] TABLE before. In my opinion we should allow
>>> for
>>>>>>>>>> these
>>>>>>>>>>>>>>> explicit declaration because in most production scenarios,
>>>>>> teams
>>>>>>>>>> have
>>>>>>>>>>>>>>> strict read/write access requirements. For example, a data
>>>>>>> science
>>>>>>>>>>> team
>>>>>>>>>>>>>>> should only consume from a event Kafka topic but should not
>>>>>>>>>>> accidently
>>>>>>>>>>>>>>> write back to the single source of truth.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 4. Time attributes: In general, I like your computed
>> columns
>>>>>>>>>> approach
>>>>>>>>>>>>>>> because it makes defining a rowtime attributes transparent
>>> and
>>>>>>>>>>> simple.
>>>>>>>>>>>>>>> However, there are downsides that we should discuss.
>>>>>>>>>>>>>>> 4a. Jarks current design means that timestamps are in the
>>>>>> schema
>>>>>>>>>>> twice.
>>>>>>>>>>>>>>> The design that is mentioned in [1] makes this more
>> flexible
>>> as
>>>>>>> it
>>>>>>>>>>>>>>> either allows to replace an existing column or add a
>> computed
>>>>>>>>>> column.
>>>>>>>>>>>>>>> 4b. We need to consider the zoo of storage systems that is
>>> out
>>>>>>>>>> there
>>>>>>>>>>>>>>> right now. Take Kafka as an example, how can we write out a
>>>>>>>>>> timestamp
>>>>>>>>>>>>>>> into the message header? We need to think of a reverse
>>>>>> operation
>>>>>>>>>> to a
>>>>>>>>>>>>>>> computed column.
>>>>>>>>>>>>>>> 4c. Does defining a watermark really fit into the schema
>> part
>>>>>> of
>>>>>>> a
>>>>>>>>>>>>>>> table? Shouldn't we separate all time attribute concerns
>>> into a
>>>>>>>>>>> special
>>>>>>>>>>>>>>> clause next to the regular schema, similar how PARTITIONED
>> BY
>>>>>>> does
>>>>>>>>>> it
>>>>>>>>>>>> in
>>>>>>>>>>>>>>> Hive?
>>>>>>>>>>>>>>> 4d. How can people come up with a custom watermark
>> strategy?
>>> I
>>>>>>>>>> guess
>>>>>>>>>>>>>>> this can not be implemented in a scalar function and would
>>>>>>> require
>>>>>>>>>>> some
>>>>>>>>>>>>>>> new type of UDF?
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 6. Partitioning and keys: Another question that the DDL
>>> design
>>>>>>>>>> should
>>>>>>>>>>>>>>> answer is how do we express primary keys (for upserts),
>>>>>>>>>> partitioning
>>>>>>>>>>>>>>> keys (for Hive, Kafka message keys). All part of the table
>>>>>>> schema?
>>>>>>>>>>>>>>> 5. Schema declaration: I find it very annoying that we want
>>> to
>>>>>>>>>> force
>>>>>>>>>>>>>>> people to declare all columns and types again even though
>>> this
>>>>>> is
>>>>>>>>>>>>>>> usually already defined in some company-wide format. I know
>>>>>> that
>>>>>>>>>>>> catalog
>>>>>>>>>>>>>>> support will greatly improve this. But if no catalog is
>> used,
>>>>>>>>>> people
>>>>>>>>>>>>>>> need to manually define a schema with 50+ fields in a Flink
>>>>>> DDL.
>>>>>>>>>>> What I
>>>>>>>>>>>>>>> actually promoted having two ways of reading data:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 1. Either the format derives its schema from the table
>>> schema.
>>>>>>>>>>>>>>> CREATE TABLE (col INT) WITH (format.type = avro)
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 2. Or the table schema can be omitted and the format schema
>>>>>>> defines
>>>>>>>>>>> the
>>>>>>>>>>>>>>> table schema (+ time attributes).
>>>>>>>>>>>>>>> CREATE TABLE WITH (format.type = avro, format.schema-file =
>>>>>>>>>>>>>>> "/my/avrofile.avsc")
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Please let me know what you think about each item. I will
>> try
>>>>>> to
>>>>>>>>>>>>>>> incorporate your feedback in [1] this week.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Regards,
>>>>>>>>>>>>>>> Timo
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> [1]
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit#heading=h.41fd6rs7b3cf
>>>>>>>>>>>>>>> Am 05.12.18 um 13:01 schrieb Jark Wu:
>>>>>>>>>>>>>>>> Hi Shuyi,
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> It's exciting to see we can make such a great progress
>> here.
>>>>>>>>>>>>>>>> Regarding to the watermark:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Watermarks can be defined on any columns (including
>>>>>>>>>> computed-column)
>>>>>>>>>>>> in
>>>>>>>>>>>>>>>> table schema.
>>>>>>>>>>>>>>>> The computed column can be computed from existing columns
>>>>>> using
>>>>>>>>>>>> builtin
>>>>>>>>>>>>>>>> functions and *UserDefinedFunctions* (ScalarFunction).
>>>>>>>>>>>>>>>> So IMO, it can work out for almost all the scenarios not
>>> only
>>>>>>>>>> common
>>>>>>>>>>>>>>>> scenarios.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I don't think using a `TimestampExtractor` to support
>> custom
>>>>>>>>>>> timestamp
>>>>>>>>>>>>>>>> extractor in SQL is a good idea. Because
>>> `TimestampExtractor`
>>>>>>>>>>>>>>>> is not a SQL standard function. If we support
>>>>>>> `TimestampExtractor`
>>>>>>>>>>> in
>>>>>>>>>>>>>>> SQL,
>>>>>>>>>>>>>>>> do we need to support CREATE FUNCTION for
>>>>>> `TimestampExtractor`?
>>>>>>>>>>>>>>>> I think `ScalarFunction` can do the same thing with
>>>>>>>>>>>>>> `TimestampExtractor`
>>>>>>>>>>>>>>>> but more powerful and standard.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> The core idea of the watermark definition syntax is that
>> the
>>>>>>>>>> schema
>>>>>>>>>>>>>> part
>>>>>>>>>>>>>>>> defines all the columns of the table, it is exactly what
>> the
>>>>>>> query
>>>>>>>>>>>>>> sees.
>>>>>>>>>>>>>>>> The watermark part is something like a primary key
>>> definition
>>>>>> or
>>>>>>>>>>>>>>> constraint
>>>>>>>>>>>>>>>> on SQL Table, it has no side effect on the schema, only
>>>>>> defines
>>>>>>>>>> what
>>>>>>>>>>>>>>>> watermark strategy is and makes which field as the rowtime
>>>>>>>>>> attribute
>>>>>>>>>>>>>>> field.
>>>>>>>>>>>>>>>> If the rowtime field is not in the existing fields, we can
>>> use
>>>>>>>>>>>> computed
>>>>>>>>>>>>>>>> column
>>>>>>>>>>>>>>>> to generate it from other existing fields. The Descriptor
>>>>>>> Pattern
>>>>>>>>>>> API
>>>>>>>>>>>>>> [1]
>>>>>>>>>>>>>>>> is very useful when writing a Table API job, but is not
>>>>>>>>>>> contradictory
>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>> Watermark DDL from my perspective.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> [1]:
>>>>>>>>>>>>>>>>
>> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
>>>>>>>>>>>>>>>> .
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Best,
>>>>>>>>>>>>>>>> Jark
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> On Wed, 5 Dec 2018 at 17:58, Shuyi Chen <
>> [hidden email]
>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>> Hi Jark and Shaoxuan,
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Thanks a lot for the summary. I think we are making great
>>>>>>>>>> progress
>>>>>>>>>>>>>> here.
>>>>>>>>>>>>>>>>> Below are my thoughts.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> *(1) watermark definition
>>>>>>>>>>>>>>>>> IMO, it's better to keep it consistent with the rowtime
>>>>>>>>>> extractors
>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>> watermark strategies defined in
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>
>> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
>>>>>>>>>>>>>>>>> .
>>>>>>>>>>>>>>>>> Using built-in functions seems to be too much for most of
>>> the
>>>>>>>>>>> common
>>>>>>>>>>>>>>>>> scenarios.
>>>>>>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
>>>>>>>>>>>>>>>>> Actually, I think we can put the source/sink type info
>> into
>>>>>> the
>>>>>>>>>>> table
>>>>>>>>>>>>>>>>> properties, so we can use CREATE TABLE.
>>>>>>>>>>>>>>>>> (3) View DDL with properties
>>>>>>>>>>>>>>>>> We can remove the view properties section now for the MVP
>>> and
>>>>>>> add
>>>>>>>>>>> it
>>>>>>>>>>>>>>> back
>>>>>>>>>>>>>>>>> later if needed.
>>>>>>>>>>>>>>>>> (4) Type Definition
>>>>>>>>>>>>>>>>> I agree we can put the type length or precision into
>> future
>>>>>>>>>>> versions.
>>>>>>>>>>>>>> As
>>>>>>>>>>>>>>>>> for the grammar difference, currently, I am using the
>>> grammar
>>>>>>> in
>>>>>>>>>>>>>> Calcite
>>>>>>>>>>>>>>>>> type DDL, but since we'll extend the parser in Flink, so
>> we
>>>>>> can
>>>>>>>>>>>>>>> definitely
>>>>>>>>>>>>>>>>> change if needed.
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Shuyi
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> On Tue, Dec 4, 2018 at 10:48 PM Jark Wu <
>> [hidden email]>
>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>> Hi Shaoxuan,
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Thanks for pointing that out. Yes, the source/sink tag
>> on
>>>>>>> create
>>>>>>>>>>>>>> table
>>>>>>>>>>>>>>> is
>>>>>>>>>>>>>>>>>> the another major difference.
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Summarize the main differences again:
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> *(1) watermark definition
>>>>>>>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
>>>>>>>>>>>>>>>>>> (3) View DDL with properties
>>>>>>>>>>>>>>>>>> (4) Type Definition
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> Best,
>>>>>>>>>>>>>>>>>> Jark
>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>> On Wed, 5 Dec 2018 at 14:08, Shaoxuan Wang <
>>>>>>> [hidden email]
>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>> Hi Jark,
>>>>>>>>>>>>>>>>>>> Thanks for the summary. Your plan for the 1st round
>>>>>>>>>>> implementation
>>>>>>>>>>>>>> of
>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>> looks good to me.
>>>>>>>>>>>>>>>>>>> Have we reached the agreement on simplifying/unifying
>>>>>> "create
>>>>>>>>>>>>>>>>>> [source/sink]
>>>>>>>>>>>>>>>>>>> table" to "create table"? "Watermark definition" and
>>>>>> "create
>>>>>>>>>>> table"
>>>>>>>>>>>>>>> are
>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>> major obstacles on the way to merge two design
>> proposals
>>>>>>> FMPOV.
>>>>>>>>>>>>>>> @Shuyi,
>>>>>>>>>>>>>>>>>> It
>>>>>>>>>>>>>>>>>>> would be great if you can spend time and respond to
>> these
>>>>>> two
>>>>>>>>>>> parts
>>>>>>>>>>>>>>>>>> first.
>>>>>>>>>>>>>>>>>>> Regards,
>>>>>>>>>>>>>>>>>>> Shaoxuan
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> On Wed, Dec 5, 2018 at 12:20 PM Jark Wu <
>>> [hidden email]>
>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> It seems that you have reviewed the DDL doc [1] that
>> Lin
>>>>>>> and I
>>>>>>>>>>>>>>>>> drafted.
>>>>>>>>>>>>>>>>>>>> This doc covers all the features running in Alibaba.
>>>>>>>>>>>>>>>>>>>> But some of features might be not needed in the first
>>>>>>> version
>>>>>>>>>> of
>>>>>>>>>>>>>>>>> Flink
>>>>>>>>>>>>>>>>>>> SQL
>>>>>>>>>>>>>>>>>>>> DDL.
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> So my suggestion would be to focus on the MVP DDLs and
>>>>>> reach
>>>>>>>>>>>>>>>>> agreement
>>>>>>>>>>>>>>>>>>> ASAP
>>>>>>>>>>>>>>>>>>>> based on the DDL draft [1] and the DDL design [2]
>> Shuyi
>>>>>>>>>>> proposed.
>>>>>>>>>>>>>>>>>>>> And we can discuss on the main differences one by one.
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> The following is the MVP DDLs should be included in
>> the
>>>>>>> first
>>>>>>>>>>>>>> version
>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>> my
>>>>>>>>>>>>>>>>>>>> opinion (feedbacks are welcome):
>>>>>>>>>>>>>>>>>>>> (1) Table DDL:
>>>>>>>>>>>>>>>>>>>>          (1.1) Type definition
>>>>>>>>>>>>>>>>>>>>          (1.2) computed column definition
>>>>>>>>>>>>>>>>>>>>          (1.3) watermark definition
>>>>>>>>>>>>>>>>>>>>          (1.4) with properties
>>>>>>>>>>>>>>>>>>>>          (1.5) table constraint (primary key/unique)
>>>>>>>>>>>>>>>>>>>>          (1.6) column nullability (nice to have)
>>>>>>>>>>>>>>>>>>>> (2) View DDL
>>>>>>>>>>>>>>>>>>>> (3) Function DDL
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> The main differences from two DDL docs (sth maybe
>>> missed,
>>>>>>>>>>> welcome
>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>> point
>>>>>>>>>>>>>>>>>>>> out):
>>>>>>>>>>>>>>>>>>>> *(1.3) watermark*: this is the main and the most
>>> important
>>>>>>>>>>>>>>>>> difference,
>>>>>>>>>>>>>>>>>> it
>>>>>>>>>>>>>>>>>>>> would be great if @Timo Walther <[hidden email]>
>>>>>>> @Fabian
>>>>>>>>>>>>>> Hueske
>>>>>>>>>>>>>>>>>>>> <[hidden email]>  give some feedbacks.
>>>>>>>>>>>>>>>>>>>>       (1.1) Type definition:
>>>>>>>>>>>>>>>>>>>>            (a) Should VARCHAR carry a length, e.g.
>>>>>>> VARCHAR(128)
>>>>>>>> ?
>>>>>>>>>>>>>>>>>>>>                 In most cases, the varchar length is
>> not
>>>>>> used
>>>>>>>>>>> because
>>>>>>>>>>>>>>> they
>>>>>>>>>>>>>>>>>> are
>>>>>>>>>>>>>>>>>>>> stored as String in Flink. But it can be used to
>>> optimize
>>>>>> in
>>>>>>>>>> the
>>>>>>>>>>>>>>>>> future
>>>>>>>>>>>>>>>>>>> if
>>>>>>>>>>>>>>>>>>>> we know the column is a fixed length VARCHAR.
>>>>>>>>>>>>>>>>>>>>                 So IMO, we can support VARCHAR with
>>> length
>>>>>> in
>>>>>>>> the
>>>>>>>>>>>>>> future,
>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>> just VARCHAR in this version.
>>>>>>>>>>>>>>>>>>>>            (b) Should DECIMAL support custom scale and
>>>>>>>> precision,
>>>>>>>>>>>> e.g.
>>>>>>>>>>>>>>>>>>>> DECIMAL(12, 5)?
>>>>>>>>>>>>>>>>>>>>                 If we clearly know the scale and
>>> precision
>>>>>> of
>>>>>>>> the
>>>>>>>>>>>>>>> Decimal,
>>>>>>>>>>>>>>>>>> we
>>>>>>>>>>>>>>>>>>>> can have some optimization on
>>>>>> serialization/deserialization.
>>>>>>>>>>> IMO,
>>>>>>>>>>>>>> we
>>>>>>>>>>>>>>>>>> can
>>>>>>>>>>>>>>>>>>>> support just support DECIMAL in this version,
>>>>>>>>>>>>>>>>>>>>                 which means DECIMAL(38, 18) as default.
>>> And
>>>>>>>>>> support
>>>>>>>>>>>>>>> custom
>>>>>>>>>>>>>>>>>>> scale
>>>>>>>>>>>>>>>>>>>> and precision in the future.
>>>>>>>>>>>>>>>>>>>>       (2) View DDL: Do we need WITH properties in View
>>> DDL
>>>>>>>>>>> (proposed
>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>> doc[2])?
>>>>>>>>>>>>>>>>>>>> What are the properties on the view used for?
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> The features could be supported and discussed in the
>>>>>> future:
>>>>>>>>>>>>>>>>>>>> (1) period definition on table
>>>>>>>>>>>>>>>>>>>> (2) Type DDL
>>>>>>>>>>>>>>>>>>>> (3) Index DDL
>>>>>>>>>>>>>>>>>>>> (4) Library DDL
>>>>>>>>>>>>>>>>>>>> (5) Drop statement
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> [1] Flink DDL draft by Lin and Jark:
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>
>> https://docs.google.com/document/d/1o16jC-AxnZoxMfHQptkKQkSC6ZDDBRhKg6gm8VGnY-k/edit#
>>>>>>>>>>>>>>>>>>>> [2] Flink SQL DDL design by Shuyi:
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>
>> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit#
>>>>>>>>>>>>>>>>>>>> Cheers,
>>>>>>>>>>>>>>>>>>>> Jark
>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>> On Thu, 29 Nov 2018 at 16:13, Shaoxuan Wang <
>>>>>>>>>>> [hidden email]>
>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>> Sure Shuyu,
>>>>>>>>>>>>>>>>>>>>> What I hope is that we can reach an agreement on DDL
>>>>>> gramma
>>>>>>>>>> as
>>>>>>>>>>>>>> soon
>>>>>>>>>>>>>>>>>> as
>>>>>>>>>>>>>>>>>>>>> possible. There are a few differences between your
>>>>>> proposal
>>>>>>>>>> and
>>>>>>>>>>>>>>>>> ours.
>>>>>>>>>>>>>>>>>>>> Once
>>>>>>>>>>>>>>>>>>>>> Lin and Jark propose our design, we can quickly
>> discuss
>>>>>> on
>>>>>>>>>> the
>>>>>>>>>>>>>>>>> those
>>>>>>>>>>>>>>>>>>>>> differences, and see how far away towards a unified
>>>>>> design.
>>>>>>>>>>>>>>>>>>>>> WRT the external catalog, I think it is an orthogonal
>>>>>>> topic,
>>>>>>>>>> we
>>>>>>>>>>>>>> can
>>>>>>>>>>>>>>>>>>>> design
>>>>>>>>>>>>>>>>>>>>> it in parallel. I believe @Xuefu, @Bowen are already
>>>>>>> working
>>>>>>>>>>> on.
>>>>>>>>>>>>>> We
>>>>>>>>>>>>>>>>>>>>> should/will definitely involve them to review the
>> final
>>>>>>>>>> design
>>>>>>>>>>> of
>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>> implementation. I would suggest that we should give
>> it
>>> a
>>>>>>>>>> higher
>>>>>>>>>>>>>>>>>>> priority
>>>>>>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>>>>>>>> the DDL implementation, as it is a crucial component
>>> for
>>>>>>> the
>>>>>>>>>>> user
>>>>>>>>>>>>>>>>>>>>> experience of SQL_CLI.
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> Regards,
>>>>>>>>>>>>>>>>>>>>> Shaoxuan
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>> On Thu, Nov 29, 2018 at 6:56 AM Shuyi Chen <
>>>>>>>>>> [hidden email]
>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Shaoxuan, Jack and Lin. We should
>>>>>> definitely
>>>>>>>>>>>>>>>>>>> collaborate
>>>>>>>>>>>>>>>>>>>>>> here, we have also our own DDL implementation
>> running
>>> in
>>>>>>>>>>>>>>>>> production
>>>>>>>>>>>>>>>>>>> for
>>>>>>>>>>>>>>>>>>>>>> almost 2 years at Uber. With the joint experience
>> from
>>>>>>> both
>>>>>>>>>>>>>>>>>>> companies,
>>>>>>>>>>>>>>>>>>>> we
>>>>>>>>>>>>>>>>>>>>>> can definitely make the Flink SQL DDL better.
>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>> As @shaoxuan suggest, Jark can come up with a doc
>> that
>>>>>>> talks
>>>>>>>>>>>>>>>>> about
>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>> current DDL design in Alibaba, and we can discuss
>> and
>>>>>>> merge
>>>>>>>>>>> them
>>>>>>>>>>>>>>>>>> into
>>>>>>>>>>>>>>>>>>>>> one,
>>>>>>>>>>>>>>>>>>>>>> make it as a FLIP, and plan the tasks for
>>>>>> implementation.
>>>>>>>>>>> Also,
>>>>>>>>>>>>>>>>> we
>>>>>>>>>>>>>>>>>>>> should
>>>>>>>>>>>>>>>>>>>>>> take into account the new external catalog effort in
>>> the
>>>>>>>>>>> design.
>>>>>>>>>>>>>>>>>> What
>>>>>>>>>>>>>>>>>>>> do
>>>>>>>>>>>>>>>>>>>>>> you guys think?
>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>> Shuyi
>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 6:45 AM Jark Wu <
>>>>>> [hidden email]
>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>>> Hi Shaoxuan,
>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>> I think summarizing it into a google doc is a good
>>>>>> idea.
>>>>>>> We
>>>>>>>>>>>>>>>>> will
>>>>>>>>>>>>>>>>>>>>> prepare
>>>>>>>>>>>>>>>>>>>>>> it
>>>>>>>>>>>>>>>>>>>>>>> in the next few days.
>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>>>>>>>> Jark
>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>> Shaoxuan Wang <[hidden email]> 于2018年11月28日周三
>>>>>>>>>> 下午9:17写道：
>>>>>>>>>>>>>>>>>>>>>>>> Hi Lin and Jark,
>>>>>>>>>>>>>>>>>>>>>>>> Thanks for sharing those details. Can you please
>>>>>>> consider
>>>>>>>>>>>>>>>>>>>> summarizing
>>>>>>>>>>>>>>>>>>>>>>> your
>>>>>>>>>>>>>>>>>>>>>>>> DDL design into a google doc.
>>>>>>>>>>>>>>>>>>>>>>>> We can still continue the discussions on Shuyi's
>>>>>>> proposal.
>>>>>>>>>>>>>>>>> But
>>>>>>>>>>>>>>>>>>>>> having a
>>>>>>>>>>>>>>>>>>>>>>>> separate google doc will be easy for the DEV to
>>>>>>>>>>>>>>>>>>>>>>> understand/comment/discuss
>>>>>>>>>>>>>>>>>>>>>>>> on your proposed DDL implementation.
>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>> Regards,
>>>>>>>>>>>>>>>>>>>>>>>> Shaoxuan
>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 7:39 PM Jark Wu <
>>>>>>> [hidden email]
>>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>> Thanks for bringing up this discussion and the
>>>>>> awesome
>>>>>>>>>>>>>>>>> work!
>>>>>>>>>>>>>>>>>> I
>>>>>>>>>>>>>>>>>>>> have
>>>>>>>>>>>>>>>>>>>>>>> left
>>>>>>>>>>>>>>>>>>>>>>>>> some comments in the doc.
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>> I want to share something more about the
>> watermark
>>>>>>>>>>>>>>>>> definition
>>>>>>>>>>>>>>>>>>>>> learned
>>>>>>>>>>>>>>>>>>>>>>>> from
>>>>>>>>>>>>>>>>>>>>>>>>> Alibaba.
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>         1.
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>         Table should be able to accept multiple
>>>>>> watermark
>>>>>>>>>>>>>>>>>>> definition.
>>>>>>>>>>>>>>>>>>>>>>>>>         Because a table may have more than one
>>> rowtime
>>>>>>>>>> field.
>>>>>>>>>>>>>>>>> For
>>>>>>>>>>>>>>>>>>>>> example,
>>>>>>>>>>>>>>>>>>>>>>> one
>>>>>>>>>>>>>>>>>>>>>>>>>         rowtime field is from existing field but
>>>>>> missing
>>>>>>> in
>>>>>>>>>>> some
>>>>>>>>>>>>>>>>>>>>> records,
>>>>>>>>>>>>>>>>>>>>>>>>> another
>>>>>>>>>>>>>>>>>>>>>>>>>         is the ingestion timestamp in Kafka but
>> not
>>>>>> very
>>>>>>>>>>>>>>>>> accurate.
>>>>>>>>>>>>>>>>>>> In
>>>>>>>>>>>>>>>>>>>>> this
>>>>>>>>>>>>>>>>>>>>>>>> case,
>>>>>>>>>>>>>>>>>>>>>>>>>         user may define two rowtime fields with
>>>>>>> watermarks
>>>>>>>>>> in
>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>> Table
>>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>> choose
>>>>>>>>>>>>>>>>>>>>>>>>>         one in different situation.
>>>>>>>>>>>>>>>>>>>>>>>>>         2.
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>         Watermark stragety always work with
>> rowtime
>>>>>> field
>>>>>>>>>>>>>>>>>> together.
>>>>>>>>>>>>>>>>>>>>>>>>> Based on the two points metioned above, I think
>> we
>>>>>>> should
>>>>>>>>>>>>>>>>>>> combine
>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>> watermark strategy and rowtime field selection
>>> (i.e.
>>>>>>>>>> which
>>>>>>>>>>>>>>>>>>>> existing
>>>>>>>>>>>>>>>>>>>>>>> field
>>>>>>>>>>>>>>>>>>>>>>>>> used to generate watermark) in one clause, so
>> that
>>> we
>>>>>>> can
>>>>>>>>>>>>>>>>>>> define
>>>>>>>>>>>>>>>>>>>>>>> multiple
>>>>>>>>>>>>>>>>>>>>>>>>> watermarks in one Table.
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>> Here I will share the watermark syntax used in
>>>>>> Alibaba
>>>>>>>>>>>>>>>>>> (simply
>>>>>>>>>>>>>>>>>>>>>>> modified):
>>>>>>>>>>>>>>>>>>>>>>>>> watermarkDefinition:
>>>>>>>>>>>>>>>>>>>>>>>>> WATERMARK [watermarkName] FOR <rowtime_field> AS
>>>>>>>>>>>>>>>>> wm_strategy
>>>>>>>>>>>>>>>>>>>>>>>>> wm_strategy:
>>>>>>>>>>>>>>>>>>>>>>>>>        BOUNDED WITH OFFSET 'string' timeUnit
>>>>>>>>>>>>>>>>>>>>>>>>> |
>>>>>>>>>>>>>>>>>>>>>>>>>        ASCENDING
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>> The “WATERMARK” keyword starts a watermark
>>>>>> definition.
>>>>>>>>>> The
>>>>>>>>>>>>>>>>>>> “FOR”
>>>>>>>>>>>>>>>>>>>>>>> keyword
>>>>>>>>>>>>>>>>>>>>>>>>> defines which existing field used to generate
>>>>>>> watermark,
>>>>>>>>>>>>>>>>> this
>>>>>>>>>>>>>>>>>>>> field
>>>>>>>>>>>>>>>>>>>>>>>> should
>>>>>>>>>>>>>>>>>>>>>>>>> already exist in the schema (we can use
>>>>>> computed-column
>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>> derive
>>>>>>>>>>>>>>>>>>>>>> from
>>>>>>>>>>>>>>>>>>>>>>>>> other fields). The “AS” keyword defines watermark
>>>>>>>>>> strategy,
>>>>>>>>>>>>>>>>>>> such
>>>>>>>>>>>>>>>>>>>> as
>>>>>>>>>>>>>>>>>>>>>>>> BOUNDED
>>>>>>>>>>>>>>>>>>>>>>>>> WITH OFFSET (covers almost all the requirements)
>>> and
>>>>>>>>>>>>>>>>>> ASCENDING.
>>>>>>>>>>>>>>>>>>>>>>>>> When the expected rowtime field does not exist in
>>> the
>>>>>>>>>>>>>>>>> schema,
>>>>>>>>>>>>>>>>>>> we
>>>>>>>>>>>>>>>>>>>>> can
>>>>>>>>>>>>>>>>>>>>>>> use
>>>>>>>>>>>>>>>>>>>>>>>>> computed-column syntax to derive it from other
>>>>>> existing
>>>>>>>>>>>>>>>>>> fields
>>>>>>>>>>>>>>>>>>>>> using
>>>>>>>>>>>>>>>>>>>>>>>>> built-in functions or user defined functions. So
>>> the
>>>>>>>>>>>>>>>>>>>>>> rowtime/watermark
>>>>>>>>>>>>>>>>>>>>>>>>> definition doesn’t need to care about
>>> “field-change”
>>>>>>>>>>>>>>>>> strategy
>>>>>>>>>>>>>>>>>>>>>>>>> (replace/add/from-field). And the proctime field
>>>>>>>>>> definition
>>>>>>>>>>>>>>>>>> can
>>>>>>>>>>>>>>>>>>>>> also
>>>>>>>>>>>>>>>>>>>>>> be
>>>>>>>>>>>>>>>>>>>>>>>>> defined using computed-column. Such as pt as
>>>>>> PROCTIME()
>>>>>>>>>>>>>>>>> which
>>>>>>>>>>>>>>>>>>>>>> defines a
>>>>>>>>>>>>>>>>>>>>>>>>> proctime field named “pt” in the schema.
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>> Looking forward to working with you guys!
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>> Best,
>>>>>>>>>>>>>>>>>>>>>>>>> Jark Wu
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>> Lin Li <[hidden email]> 于2018年11月28日周三
>>>>>>> 下午6:33写道：
>>>>>>>>>>>>>>>>>>>>>>>>>> @Shuyi
>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks for the proposal!  We have a simple DDL
>>>>>>>>>>>>>>>>>> implementation
>>>>>>>>>>>>>>>>>>>>>>> (extends
>>>>>>>>>>>>>>>>>>>>>>>>>> Calcite's parser) which been running for almost
>>> two
>>>>>>>>>> years
>>>>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>>>>>>>>>> production
>>>>>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>>> works well.
>>>>>>>>>>>>>>>>>>>>>>>>>> I think the most valued things we'd learned is
>>>>>> keeping
>>>>>>>>>>>>>>>>>>>> simplicity
>>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>>> standard compliance.
>>>>>>>>>>>>>>>>>>>>>>>>>> Here's the approximate grammar, FYI
>>>>>>>>>>>>>>>>>>>>>>>>>> CREATE TABLE
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> CREATE TABLE tableName(
>>>>>>>>>>>>>>>>>>>>>>>>>>              columnDefinition [,
>> columnDefinition]*
>>>>>>>>>>>>>>>>>>>>>>>>>>              [ computedColumnDefinition [,
>>>>>>>>>>>>>>>>>>>> computedColumnDefinition]*
>>>>>>>>>>>>>>>>>>>>> ]
>>>>>>>>>>>>>>>>>>>>>>>>>>              [ tableConstraint [,
>>> tableConstraint]* ]
>>>>>>>>>>>>>>>>>>>>>>>>>>              [ tableIndex [, tableIndex]* ]
>>>>>>>>>>>>>>>>>>>>>>>>>>          [ PERIOD FOR SYSTEM_TIME ]
>>>>>>>>>>>>>>>>>>>>>>>>>>              [ WATERMARK watermarkName FOR
>>>>>> rowTimeColumn
>>>>>>>> AS
>>>>>>>>>>>>>>>>>>>>>>>>>> withOffset(rowTimeColumn, offset) ]     ) [
>> WITH (
>>>>>>>>>>>>>>>>>>> tableOption
>>>>>>>>>>>>>>>>>>>> [
>>>>>>>>>>>>>>>>>>>>> ,
>>>>>>>>>>>>>>>>>>>>>>>>>> tableOption]* ) ] [ ; ]
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> columnDefinition ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              columnName dataType [ NOT NULL ]
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> dataType  ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              {
>>>>>>>>>>>>>>>>>>>>>>>>>>                [ VARCHAR ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ BOOLEAN ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ TINYINT ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ SMALLINT ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ INT ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ BIGINT ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ FLOAT ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ DECIMAL ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ DOUBLE ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ DATE ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ TIME ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ TIMESTAMP ]
>>>>>>>>>>>>>>>>>>>>>>>>>>                | [ VARBINARY ]
>>>>>>>>>>>>>>>>>>>>>>>>>>              }
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> computedColumnDefinition ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              columnName AS
>> computedColumnExpression
>>>>>>>>>>>>>>>>>>>>>>>>>> tableConstraint ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>          { PRIMARY KEY | UNIQUE }
>>>>>>>>>>>>>>>>>>>>>>>>>>              (columnName [, columnName]* )
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> tableIndex ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              [ UNIQUE ] INDEX indexName
>>>>>>>>>>>>>>>>>>>>>>>>>>               (columnName [, columnName]* )
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> rowTimeColumn ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              columnName
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> tableOption ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              property=value
>>>>>>>>>>>>>>>>>>>>>>>>>>              offset ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              positive integer (unit: ms)
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> CREATE VIEW
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> CREATE VIEW viewName
>>>>>>>>>>>>>>>>>>>>>>>>>>        [
>>>>>>>>>>>>>>>>>>>>>>>>>>              ( columnName [, columnName]* )
>>>>>>>>>>>>>>>>>>>>>>>>>>        ]
>>>>>>>>>>>>>>>>>>>>>>>>>>              AS queryStatement;
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> CREATE FUNCTION
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>       CREATE FUNCTION functionName
>>>>>>>>>>>>>>>>>>>>>>>>>>        AS 'className';
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>       className ::=
>>>>>>>>>>>>>>>>>>>>>>>>>>              fully qualified name
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi Chen <[hidden email]> 于2018年11月28日周三
>>>>>>>>>> 上午3:28写道：
>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Timo and Xuefu. Yes, I think we
>> can
>>>>>>>>>>>>>>>>>> finalize
>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>> design
>>>>>>>>>>>>>>>>>>>>>>>>> doc
>>>>>>>>>>>>>>>>>>>>>>>>>>> first and start implementation w/o the unified
>>>>>>>>>>>>>>>>> connector
>>>>>>>>>>>>>>>>>>> API
>>>>>>>>>>>>>>>>>>>>>> ready
>>>>>>>>>>>>>>>>>>>>>>> by
>>>>>>>>>>>>>>>>>>>>>>>>>>> skipping some featue.
>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu, I like the idea of making Flink specific
>>>>>>>>>>>>>>>>>> properties
>>>>>>>>>>>>>>>>>>>> into
>>>>>>>>>>>>>>>>>>>>>>>> generic
>>>>>>>>>>>>>>>>>>>>>>>>>>> key-value pairs, so that it will make
>> integration
>>>>>>> with
>>>>>>>>>>>>>>>>>> Hive
>>>>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>>> (or
>>>>>>>>>>>>>>>>>>>>>>>>>> others,
>>>>>>>>>>>>>>>>>>>>>>>>>>> e.g. Beam DDL) easier.
>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>> I'll run a final pass over the design doc and
>>>>>>> finalize
>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>> design
>>>>>>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>> next few days. And we can start creating tasks
>>> and
>>>>>>>>>>>>>>>>>>>> collaborate
>>>>>>>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>> implementation. Thanks a lot for all the
>> comments
>>>>>> and
>>>>>>>>>>>>>>>>>>> inputs.
>>>>>>>>>>>>>>>>>>>>>>>>>>> Cheers!
>>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi
>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>> On Tue, Nov 27, 2018 at 7:02 AM Zhang, Xuefu <
>>>>>>>>>>>>>>>>>>>>>>>> [hidden email]>
>>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Yeah! I agree with Timo that DDL can actually
>>>>>>> proceed
>>>>>>>>>>>>>>>>>> w/o
>>>>>>>>>>>>>>>>>>>>> being
>>>>>>>>>>>>>>>>>>>>>>>>> blocked
>>>>>>>>>>>>>>>>>>>>>>>>>>> by
>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector API. We can leave the unknown out
>>> while
>>>>>>>>>>>>>>>>>>> defining
>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>> basic
>>>>>>>>>>>>>>>>>>>>>>>>>>> syntax.
>>>>>>>>>>>>>>>>>>>>>>>>>>>> @Shuyi
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> As commented in the doc, I think we can
>> probably
>>>>>>>>>>>>>>>>> stick
>>>>>>>>>>>>>>>>>>> with
>>>>>>>>>>>>>>>>>>>>>>> simple
>>>>>>>>>>>>>>>>>>>>>>>>>> syntax
>>>>>>>>>>>>>>>>>>>>>>>>>>>> with general properties, without extending the
>>>>>>> syntax
>>>>>>>>>>>>>>>>>> too
>>>>>>>>>>>>>>>>>>>>> much
>>>>>>>>>>>>>>>>>>>>>>> that
>>>>>>>>>>>>>>>>>>>>>>>>> it
>>>>>>>>>>>>>>>>>>>>>>>>>>>> mimics the descriptor API.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Part of our effort on Flink-Hive integration
>> is
>>>>>> also
>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>> make
>>>>>>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>>>>>> syntax
>>>>>>>>>>>>>>>>>>>>>>>>>>>> compatible with Hive's. The one in the current
>>>>>>>>>>>>>>>>> proposal
>>>>>>>>>>>>>>>>>>>> seems
>>>>>>>>>>>>>>>>>>>>>>>> making
>>>>>>>>>>>>>>>>>>>>>>>>>> our
>>>>>>>>>>>>>>>>>>>>>>>>>>>> effort more challenging.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> We can help and collaborate. At this moment, I
>>>>>> think
>>>>>>>>>>>>>>>>> we
>>>>>>>>>>>>>>>>>>> can
>>>>>>>>>>>>>>>>>>>>>>>> finalize
>>>>>>>>>>>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>>>>>>>>>>>>>>> the proposal and then we can divide the tasks
>>> for
>>>>>>>>>>>>>>>>>> better
>>>>>>>>>>>>>>>>>>>>>>>>> collaboration.
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Please let me know if there are  any questions
>>> or
>>>>>>>>>>>>>>>>>>>>> suggestions.
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> ------------------------------------------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Sender:Timo Walther <[hidden email]>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Sent at:2018 Nov 27 (Tue) 16:21
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Recipient:dev <[hidden email]>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks for offering your help here, Xuefu. It
>>>>>> would
>>>>>>>>>>>>>>>>> be
>>>>>>>>>>>>>>>>>>>> great
>>>>>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>>>>>> move
>>>>>>>>>>>>>>>>>>>>>>>>>>>> these efforts forward. I agree that the DDL is
>>>>>>>>>>>>>>>>> somehow
>>>>>>>>>>>>>>>>>>>>> releated
>>>>>>>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>>> unified connector API design but we can also
>>> start
>>>>>>>>>>>>>>>>> with
>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>> basic
>>>>>>>>>>>>>>>>>>>>>>>>>>>> functionality now and evolve the DDL during
>> this
>>>>>>>>>>>>>>>>>> release
>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>> next
>>>>>>>>>>>>>>>>>>>>>>>>>>> releases.
>>>>>>>>>>>>>>>>>>>>>>>>>>>> For example, we could identify the MVP DDL
>>> syntax
>>>>>>>>>>>>>>>>> that
>>>>>>>>>>>>>>>>>>>> skips
>>>>>>>>>>>>>>>>>>>>>>>> defining
>>>>>>>>>>>>>>>>>>>>>>>>>>>> key constraints and maybe even time
>> attributes.
>>>>>> This
>>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>> could
>>>>>>>>>>>>>>>>>>>>>> be
>>>>>>>>>>>>>>>>>>>>>>>>> used
>>>>>>>>>>>>>>>>>>>>>>>>>>>> for batch usecases, ETL, and materializing SQL
>>>>>>>>>>>>>>>>> queries
>>>>>>>>>>>>>>>>>>> (no
>>>>>>>>>>>>>>>>>>>>> time
>>>>>>>>>>>>>>>>>>>>>>>>>>>> operations like windows).
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> The unified connector API is high on our
>>> priority
>>>>>>>>>>>>>>>>> list
>>>>>>>>>>>>>>>>>>> for
>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>> 1.8
>>>>>>>>>>>>>>>>>>>>>>>>>>>> release. I will try to update the document
>> until
>>>>>> mid
>>>>>>>>>>>>>>>>> of
>>>>>>>>>>>>>>>>>>>> next
>>>>>>>>>>>>>>>>>>>>>>> week.
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Regards,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Timo
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Am 27.11.18 um 08:08 schrieb Shuyi Chen:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Xuefu. I was busy for some
>> other
>>>>>>>>>>>>>>>>> stuff
>>>>>>>>>>>>>>>>>>> for
>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>> last 2
>>>>>>>>>>>>>>>>>>>>>>>>>>>> weeks,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> but we are definitely interested in moving
>> this
>>>>>>>>>>>>>>>>>>> forward.
>>>>>>>>>>>>>>>>>>>> I
>>>>>>>>>>>>>>>>>>>>>>> think
>>>>>>>>>>>>>>>>>>>>>>>>> once
>>>>>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> unified connector API design [1] is done, we
>>> can
>>>>>>>>>>>>>>>>>>> finalize
>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>>>>>>>> design
>>>>>>>>>>>>>>>>>>>>>>>>>>>> as
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> well and start creating concrete subtasks to
>>>>>>>>>>>>>>>>>>> collaborate
>>>>>>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> implementation with the community.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Mon, Nov 26, 2018 at 7:01 PM Zhang, Xuefu
>> <
>>>>>>>>>>>>>>>>>>>>>>>>>> [hidden email]>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I'm wondering if you folks still have the
>>>>>>>>>>>>>>>>> bandwidth
>>>>>>>>>>>>>>>>>>>>> working
>>>>>>>>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>>>>>>>>>>>> this.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> We have some dedicated resource and like to
>>> move
>>>>>>>>>>>>>>>>>> this
>>>>>>>>>>>>>>>>>>>>>> forward.
>>>>>>>>>>>>>>>>>>>>>>>> We
>>>>>>>>>>>>>>>>>>>>>>>>>> can
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> collaborate.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>> ------------------------------------------------------------------
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 发件人：wenlong.lwl<[hidden email]>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 日 期：2018年11月05日 11:15:35
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 收件人：<[hidden email]>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 主 题：Re: [DISCUSS] Flink SQL DDL Design
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi, Shuyi, thanks for the proposal.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I have two concerns about the table ddl:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1. how about remove the source/sink mark
>> from
>>>>>> the
>>>>>>>>>>>>>>>>>> ddl,
>>>>>>>>>>>>>>>>>>>>>> because
>>>>>>>>>>>>>>>>>>>>>>>> it
>>>>>>>>>>>>>>>>>>>>>>>>> is
>>>>>>>>>>>>>>>>>>>>>>>>>>> not
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> necessary, the framework determine the table
>>>>>>>>>>>>>>>>>> referred
>>>>>>>>>>>>>>>>>>>> is a
>>>>>>>>>>>>>>>>>>>>>>>> source
>>>>>>>>>>>>>>>>>>>>>>>>>> or a
>>>>>>>>>>>>>>>>>>>>>>>>>>>> sink
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> according to the context of the query using
>>> the
>>>>>>>>>>>>>>>>>> table.
>>>>>>>>>>>>>>>>>>>> it
>>>>>>>>>>>>>>>>>>>>>> will
>>>>>>>>>>>>>>>>>>>>>>>> be
>>>>>>>>>>>>>>>>>>>>>>>>>> more
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> convenient for use defining a table which
>> can
>>> be
>>>>>>>>>>>>>>>>>> both
>>>>>>>>>>>>>>>>>>> a
>>>>>>>>>>>>>>>>>>>>>> source
>>>>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>>>> sink,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and more convenient for catalog to
>> persistent
>>>>>> and
>>>>>>>>>>>>>>>>>>> manage
>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>> meta
>>>>>>>>>>>>>>>>>>>>>>>>>>> infos.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 2. how about just keeping one pure string
>> map
>>> as
>>>>>>>>>>>>>>>>>>>>> parameters
>>>>>>>>>>>>>>>>>>>>>>> for
>>>>>>>>>>>>>>>>>>>>>>>>>> table,
>>>>>>>>>>>>>>>>>>>>>>>>>>>> like
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> create tabe Kafka10SourceTable (
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> intField INTEGER,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> stringField VARCHAR(128),
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> longField BIGINT,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> rowTimeField TIMESTAMP
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ) with (
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.type = ’kafka’,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.property-version = ’1’,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.version = ’0.10’,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.topic =
>>> ‘test-kafka-topic’,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.startup-mode =
>>>>>>>>>>>>>>>>> ‘latest-offset’,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.specific-offset =
>>> ‘offset’,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> format.type = 'json'
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> format.prperties.version=’1’,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> format.derive-schema = 'true'
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> );
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Because:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1. in TableFactory, what user use is a
>> string
>>>>>> map
>>>>>>>>>>>>>>>>>>>>>> properties,
>>>>>>>>>>>>>>>>>>>>>>>>>> defining
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> parameters by string-map can be the closest
>>> way
>>>>>> to
>>>>>>>>>>>>>>>>>>>> mapping
>>>>>>>>>>>>>>>>>>>>>> how
>>>>>>>>>>>>>>>>>>>>>>>>> user
>>>>>>>>>>>>>>>>>>>>>>>>>>> use
>>>>>>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> parameters.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 2. The table descriptor can be extended by
>>> user,
>>>>>>>>>>>>>>>>>> like
>>>>>>>>>>>>>>>>>>>> what
>>>>>>>>>>>>>>>>>>>>>> is
>>>>>>>>>>>>>>>>>>>>>>>> done
>>>>>>>>>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>>>>>>>>> Kafka
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and Json, it means that the parameter keys
>> in
>>>>>>>>>>>>>>>>>>> connector
>>>>>>>>>>>>>>>>>>>> or
>>>>>>>>>>>>>>>>>>>>>>>> format
>>>>>>>>>>>>>>>>>>>>>>>>>> can
>>>>>>>>>>>>>>>>>>>>>>>>>>> be
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> different in different implementation, we
>> can
>>>>>> not
>>>>>>>>>>>>>>>>>>>> restrict
>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>> key
>>>>>>>>>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>>>>>>>> a
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> specified set, so we need a map in connector
>>>>>> scope
>>>>>>>>>>>>>>>>>>> and a
>>>>>>>>>>>>>>>>>>>>> map
>>>>>>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties scope. why not just
>> give
>>>>>>>>>>>>>>>>> user a
>>>>>>>>>>>>>>>>>>>>> single
>>>>>>>>>>>>>>>>>>>>>>> map,
>>>>>>>>>>>>>>>>>>>>>>>>> let
>>>>>>>>>>>>>>>>>>>>>>>>>>>> them
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> put parameters in a format they like, which
>> is
>>>>>>>>>>>>>>>>> also
>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>> simplest
>>>>>>>>>>>>>>>>>>>>>>>>> way
>>>>>>>>>>>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> implement DDL parser.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 3. whether we can define a format clause or
>>> not,
>>>>>>>>>>>>>>>>>>> depends
>>>>>>>>>>>>>>>>>>>>> on
>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> implementation of the connector, using
>>> different
>>>>>>>>>>>>>>>>>>> clause
>>>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>>>>> may
>>>>>>>>>>>>>>>>>>>>>>>>>>> make
>>>>>>>>>>>>>>>>>>>>>>>>>>>> a
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> misunderstanding that we can combine the
>>>>>>>>>>>>>>>>> connectors
>>>>>>>>>>>>>>>>>>> with
>>>>>>>>>>>>>>>>>>>>>>>> arbitrary
>>>>>>>>>>>>>>>>>>>>>>>>>>>> formats,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> which may not work actually.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Sun, 4 Nov 2018 at 18:25, Dominik
>> Wosiński
>>> <
>>>>>>>>>>>>>>>>>>>>>>> [hidden email]
>>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> +1, Thanks for the proposal.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I guess this is a long-awaited change. This
>>> can
>>>>>>>>>>>>>>>>>>> vastly
>>>>>>>>>>>>>>>>>>>>>>> increase
>>>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> functionalities of the SQL Client as it
>> will
>>> be
>>>>>>>>>>>>>>>>>>>> possible
>>>>>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>>>>> use
>>>>>>>>>>>>>>>>>>>>>>>>>>> complex
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> extensions like for example those provided
>> by
>>>>>>>>>>>>>>>>>> Apache
>>>>>>>>>>>>>>>>>>>>>>> Bahir[1].
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Best Regards,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Dom.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> https://github.com/apache/bahir-flink
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> sob., 3 lis 2018 o 17:17 Rong Rong <
>>>>>>>>>>>>>>>>>>>> [hidden email]>
>>>>>>>>>>>>>>>>>>>>>>>>>> napisał(a):
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> +1. Thanks for putting the proposal
>> together
>>>>>>>>>>>>>>>>>> Shuyi.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL has been brought up in a couple of
>> times
>>>>>>>>>>>>>>>>>>>> previously
>>>>>>>>>>>>>>>>>>>>>>> [1,2].
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Utilizing
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL will definitely be a great extension
>> to
>>>>>> the
>>>>>>>>>>>>>>>>>>>> current
>>>>>>>>>>>>>>>>>>>>>>> Flink
>>>>>>>>>>>>>>>>>>>>>>>>> SQL
>>>>>>>>>>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> systematically support some of the
>>> previously
>>>>>>>>>>>>>>>>>>> brought
>>>>>>>>>>>>>>>>>>>> up
>>>>>>>>>>>>>>>>>>>>>>>>> features
>>>>>>>>>>>>>>>>>>>>>>>>>>> such
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> as
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]. And it will also be beneficial to see
>>> the
>>>>>>>>>>>>>>>>>>>> document
>>>>>>>>>>>>>>>>>>>>>>>> closely
>>>>>>>>>>>>>>>>>>>>>>>>>>>> aligned
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> with the previous discussion for unified
>> SQL
>>>>>>>>>>>>>>>>>>> connector
>>>>>>>>>>>>>>>>>>>>> API
>>>>>>>>>>>>>>>>>>>>>>>> [4].
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I also left a few comments on the doc.
>>> Looking
>>>>>>>>>>>>>>>>>>> forward
>>>>>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>>>>>>> alignment
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> with the other couple of efforts and
>>>>>>>>>>>>>>>>> contributing
>>>>>>>>>>>>>>>>>> to
>>>>>>>>>>>>>>>>>>>>> them!
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Best,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Rong
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> http://mail-archives.apache.org/mod_mbox/flink-dev/201805.mbox/%3CCAMZk55ZTJA7MkCK1Qu4gLPu1P9neqCfHZtTcgLfrFjfO4Xv5YQ%40mail.gmail.com%3E
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3CDC070534-0782-4AFD-8A85-8A82B384B8F7%40gmail.com%3E
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
>>>>>>>>>>>>>>>>>>> https://issues.apache.org/jira/browse/FLINK-8003
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [4]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3C6676cb66-6f31-23e1-eff5-2e9c19f88483@...%3E
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Fri, Nov 2, 2018 at 10:22 AM Bowen Li <
>>>>>>>>>>>>>>>>>>>>>>> [hidden email]
>>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks Shuyi!
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I left some comments there. I think the
>>>>>> design
>>>>>>>>>>>>>>>>> of
>>>>>>>>>>>>>>>>>>> SQL
>>>>>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Flink-Hive
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration/External catalog enhancements
>>>>>> will
>>>>>>>>>>>>>>>>>> work
>>>>>>>>>>>>>>>>>>>>>> closely
>>>>>>>>>>>>>>>>>>>>>>>>> with
>>>>>>>>>>>>>>>>>>>>>>>>>>> each
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> other. Hope we are well aligned on the
>>>>>>>>>>>>>>>>> directions
>>>>>>>>>>>>>>>>>>> of
>>>>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>> two
>>>>>>>>>>>>>>>>>>>>>>>>>>> designs,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and I
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> look forward to working with you guys on
>>>>>> both!
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bowen
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Thu, Nov 1, 2018 at 10:57 PM Shuyi
>> Chen
>>> <
>>>>>>>>>>>>>>>>>>>>>>>> [hidden email]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi everyone,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL DDL support has been a long-time ask
>>>>>> from
>>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>>> community.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Current
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Flink
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL support only DML (e.g. SELECT and
>>> INSERT
>>>>>>>>>>>>>>>>>>>>>> statements).
>>>>>>>>>>>>>>>>>>>>>>> In
>>>>>>>>>>>>>>>>>>>>>>>>> its
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> current
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> form, Flink SQL users still need to
>>>>>>>>>>>>>>>>>> define/create
>>>>>>>>>>>>>>>>>>>>> table
>>>>>>>>>>>>>>>>>>>>>>>>> sources
>>>>>>>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> sinks
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> programmatically in Java/Scala. Also, in
>>> SQL
>>>>>>>>>>>>>>>>>>> Client,
>>>>>>>>>>>>>>>>>>>>>>> without
>>>>>>>>>>>>>>>>>>>>>>>>> DDL
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> support,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the current implementation does not
>> allow
>>>>>>>>>>>>>>>>>>> dynamical
>>>>>>>>>>>>>>>>>>>>>>> creation
>>>>>>>>>>>>>>>>>>>>>>>>> of
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> table,
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> type
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> or functions with SQL, this adds
>> friction
>>>>>> for
>>>>>>>>>>>>>>>>>> its
>>>>>>>>>>>>>>>>>>>>>>> adoption.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I drafted a design doc [1] with a few
>>> other
>>>>>>>>>>>>>>>>>>>> community
>>>>>>>>>>>>>>>>>>>>>>>> members
>>>>>>>>>>>>>>>>>>>>>>>>>> that
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> proposes
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the design and implementation for adding
>>> DDL
>>>>>>>>>>>>>>>>>>> support
>>>>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>>>>> Flink.
>>>>>>>>>>>>>>>>>>>>>>>>>> The
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> initial
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> design considers DDL for table, view,
>>> type,
>>>>>>>>>>>>>>>>>>> library
>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>>> function.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> It
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> will
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> be great to get feedback on the design
>>> from
>>>>>>>>>>>>>>>>> the
>>>>>>>>>>>>>>>>>>>>>> community,
>>>>>>>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> align
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> with
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> latest effort in unified SQL connector
>> API
>>>>>> [2]
>>>>>>>>>>>>>>>>>> and
>>>>>>>>>>>>>>>>>>>>> Flink
>>>>>>>>>>>>>>>>>>>>>>>> Hive
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3].
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Any feedback is highly appreciated.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi Chen
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit?usp=sharing
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> https://docs.google.com/document/d/1SkppRD_rE3uOKSN-LuZCqn4f7dz0zW5aa6T_hBZq5_o/edit?usp=sharing
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
>>>>>>>>>>>>>>>>> somehow
>>>>>>>>>>>>>>>>>>>>> connect
>>>>>>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>>>>>> your
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> future."
>>>>>>>>>>>>>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
>> somehow
>>>>>>>>>>>>>>>>> connect
>>>>>>>>>>>>>>>>>> in
>>>>>>>>>>>>>>>>>>>>> your
>>>>>>>>>>>>>>>>>>>>>>>>> future."
>>>>>>>>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow
>>> connect
>>>>>>> in
>>>>>>>>>>> your
>>>>>>>>>>>>>>>>>>>> future."
>>>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow connect
>> in
>>>>>>> your
>>>>>>>>>>>>>>> future."
>>>>>>>>>>>>>>>
>>>>>>> --
>>>>>>> "So you have to trust that the dots will somehow connect in your
>>>> future."
>>>>
>>> --
>>> "So you have to trust that the dots will somehow connect in your future."
>>>

[Jark Wu-2]

Hi Timo,

I think I get your point why it would be better to put Table Update Mode in
MVP. But because this is a sophisticated problem, we need to think about it
carefully and need some discussions offline. We will reach out to here when
we have a clear design.


8). Support row/map/array data type
Do you mean how to distinguish int[] and Integer[]?  Yes, maybe we need to
support NULL/NOT NULL just for array elements, such as: ARRAY<INT NOT NULL>
is int[], ARRAY<INT> is Integer[].


Cheers,
Jark

On Fri, 14 Dec 2018 at 19:46, Timo Walther <[hidden email]> wrote:

> Hi all,
>
> I think we should discuss what we consider an MVP DDL. For me, an MVP
> DDL was to just focus on a CREATE TABLE statement. It would be great to
> come up with a solution that finally solves the issue of connecting
> different kind of systems. One reason why we postponed DDL statements
> for quite some time is that we cannot change it easily once released.
>
> However, the current state of the discussion can be summarized by the
> following functionality:
>
> 1. Only support append source tables (because the distinction of
> update/retract table is not clear).
> 2. Only support append and update sink tables (because a changeflag is
> missing).
> 3. Don't support outputting to Kafka with time attributes (because we
> cannot set a timestamp).
>
> Personally, I would like to have more use cases enabled by solving the
> header timestamps and change flag discussion. And I don't see a reason
> why we have to rush here.
>
> 8). Support row/map/array data type
> How do we want to support object arrays vs. primitive arrays? Currently,
> we need to make this clear distinction for between external system and
> Java [1] (E.g. byte[] arrays vs. object arrays) and users can choose
> between Types.PRIMITIVE_ARRAY and Types.OBJECT_ARRAY. Otherwise we need
> to support NULL/NOT NULL for array elements.
>
> 4) Event-Time Attributes and Watermarks
> I completely agree with Rong here. `ts AS SYSTEMROWTIME()` indicates
> that the system takes care of this column and for unification this would
> mean both for sources and sinks. It is still a computed column but gives
> hints to connectors. Implementing connectors can choose if they want to
> use this hint or not. The Flink Kafka connector would make use of it.
> @Jark: I think a PERSISTED keyword would confuse users (as shown by your
> Stackoverflow question) and would only make sense for SYSTEMROWTIME and
> no other computed column.
>
> 3) SOURCE / SINK / BOTH
> @Jark: My initial suggestion was to make the SOURCE/SINK optional such
> that users can only use CREATE TABLE depending on the use case. But as I
> said before, since I cannot find support here, we can drop the keywords.
>
> 7) Table Update Mode
> @Jark: The questions that you posted are exactly the ones that we should
> find an answer for. Because a DDL should just be the front end to the
> characteristics of an engine. After thinking about it again a change
> flag is actually more similar to a PARTITION BY clause because it
> defines a field that is not in the table's schema but in the schema of
> the physical format. However, the columns defined by a PARTITION BY are
> shown when describing/projecting a table whereas a change flag column
> must not be shown.
>
> If a table source supports append, upserts, and retractions, we need a
> way to express how we want to connect to the system.
>
> hasPrimaryKey() && !hasChangeFlag() -> append mode
> hasPrimaryKey() && hasChangeFlag() -> upsert mode
> !hasPrimaryKey() && hasChangeFlag() -> retract mode
>
> Are we fine with this?
>
> Regarding reading `topic`, `partition`, `offset` or custom properties
> from message headers. I already discussed this in my unified connector
> document. We don't need built-in functions for all these properties.
> Those things depend on the connector and format, it is their
> responsibility to extend the table schema in order to expose those
> properties (e.g. by providing a Map<String, String> for all these kind
> of properties).
>
> Example:
>
> CREATE TABLE myTopic (
>      col1 INT,
>      col2 VARCHAR,
>      col3 MAP<VARCHAR, VARCHAR>,
>      col4 AS SYSTEMROWTIME()
> )
> PARTITION BY (col0 LONG)
> WITH (
>    connector.type = kafka
>    format.type = key-value-metadata
>    format.key-format.type = avro
>    format.value-format.type = json
> )
>
> The format defines to use a KeyedDeserializationSchema that extends the
> schema by a metadata column. The PARTITION BY declares the columns for
> Kafka's key in Avro format. col1 till col2 are Kafka's JSON columns.
>
> Thanks for your feedback,
> Timo
>
> [1]
>
> https://ci.apache.org/projects/flink/flink-docs-release-1.7/dev/table/connect.html#type-strings
>
>
> Am 13.12.18 um 09:50 schrieb Jark Wu:
> > Hi all,
> >
> > Here are a bunch of my thoughts:
> >
> > 8). support row/map/array data type
> > That's fine with me if we want to support them in the MVP. In my mind, we
> > can have the field type syntax like this:
> >
> > ```
> > filedType ::=
> >              {
> >                  simpleType
> >               | MAP<simpleType, fieldType>
> >               | ARRAY<fieldType>
> >               | ROW<columnDefinition [, columnDefinition]*>
> >              }
> > ```
> >
> > I have included this in @Shuyi's summary doc [1] . Please leave feedbacks
> > there!
> >
> > [1]
> >
> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit
> >
> > 3) SOURCE / SINK / BOTH
> > @Timo, CREATE TABLE statement is registering a virtual table in the
> session
> > or catalog. I don't think it is immutable, as we might also want to
> support
> > CREATE INDEX statements in the future. On the other hand, ACL is not a
> part
> > of the table definition, it should belong to the permission system which
> is
> > usually stored in somewhere else. So GRANT/INVOKE sounds like a more
> > standard option.
> >
> > 7) Table Update Mode
> > I agree with @Shuyi that table update mode can be left out from the MVP.
> > Because IMO, the update mode will not break the current MVP design. It
> > should be something to add, like the CHANGE_FLAG you proposed. We can
> > continue this discussion when we finalize the MVP.
> >
> > Meanwhile, the update mode is a big topic which may involve several weeks
> > to discuss. For example, (a) do we support CHANGE_FLAG when the table
> > supports upsert (or when the table defined a primary key)?  (b) the
> > CHANGE_FLAG should support write and read both. (c) currently, we only
> > support true (add) and false (retract) flag type, are they enough? (d)
> How
> > to connect an external storage which also support insert/delete flag like
> > mysql binlog?
> >
> > Regarding to the CHANGE_FLAG @Timo proposed, I think this is a good
> > direction. But should isRetraction be a physical field and make
> CHANGE_FLAG
> > like a constraint on that? If yes, then what the type of isRetraction?
> >
> > 4.b) Ingesting and writing timestamps to systems.
> > @Shuyi, PERSISTED can solve the problem of the field is not physically
> > stored. However, it doesn't solve the problem that how to write a field
> > back to the computed column, because "A computed column cannot be the
> > target of an INSERT or UPDATE statement" even if the computed column is
> > persisted. If we want to write a rowtime back the the external system,
> the
> > DML should look like this: "INSERT INTO sink SELECT a, rowtime FROM
> > source". The point is that the `rowtime` must be specified in the INSERT
> > statement, that's why I hope the `rowtime` field in Table is not a
> computed
> > column. See more information about PERSISTED [2] [3].
> >
> > Another point to consider is SYSTEMROWTIME() only solve reading timestamp
> > from message header in systems. There are many similar requirements here,
> > such as reading `topic`, `partition`, `offset` or custom properties from
> > message headers, do we plan to support a bunch of built-in functions like
> > SYSTEMROWTIME()?  Do we have some clean and easy way for this?
> >
> > [2]:
> >
> https://docs.microsoft.com/en-us/sql/t-sql/statements/alter-table-computed-column-definition-transact-sql?view=sql-server-2017
> > [3]:
> >
> https://stackoverflow.com/questions/51390531/sql-server-persisted-computed-columns-versus-actual-normal-column
> >
> > Looking forward to collaborate with you guys!
> >
> > Best,
> > Jark
> >
> >
> > On Thu, 13 Dec 2018 at 01:38, Rong Rong <[hidden email]> wrote:
> >
> >> Thanks for the summary effort @shuyi. Sorry for jumping in the
> discussion
> >> so late.
> >>
> >> As of the scope of MVP, I think we might want to consider adding "table
> >> update mode" problem to it. I agree with @timo that might not be easily
> >> changed in the future if the flags has to be part of the schema/column
> >> definition.
> >>
> >> Regarding the components under discussion.
> >> 4) Event-Time Attributes and Watermarks
> >> b, c) I actually like the special indicator way @fabian suggested to
> hint
> >> Flink to read time attributes directly from the system not the data
> `(ts AS
> >> SYSTEMROWTIME())`. It should also address the "compute field not
> emitted"
> >> problem by carrying the "virtual column" concept like @shuyi suggested.
> >> However if I understand correctly, this also required to be defined as
> part
> >> of the schema/column definition.
> >>
> >> 3) SOURCE / SINK / BOTH
> >> +1 on not adding properties to `CREATE TABLE` to manage ACL/permission.
> >>
> >> On a higher level, I think one question I have is whether we can
> >> definitively come to an agreement that the features under discussion
> (and
> >> potential solutions) can be cleanly adjusted/added from what we are
> >> providing on MVP (e.g. the schema/column definition might be hard to
> >> achieve but if we all agree ACL/permission should not be part of the
> >> `CREATE TABLE` and a decision can be made later). @shuyi I can also
> help in
> >> drafting the FLIP doc by summarizing the features under discussion and
> the
> >> concerns to whether included in the MVP, so that we can carry on the
> >> discussions alongside with the MVP implementation effort. I think each
> one
> >> of these features deserves a subsection dedicated for it.
> >>
> >> Many thanks,
> >> Rong
> >>
> >>
> >> On Wed, Dec 12, 2018 at 1:14 AM Shuyi Chen <[hidden email]> wrote:
> >>
> >>> Hi all,
> >>>
> >>> I summarize the MVP based on the features that we agreed upon. For
> table
> >>> update mode and custom watermark strategy and ts extractor, I found
> there
> >>> are some discussions, so I decided to leave them out for the MVP.
> >>> For row/map/array data type, I think we can add it as well if everyone
> >>> agrees.
> >>>
> >>>
> >>> 4) Event-Time Attributes and Watermarks
> >>> Cited from SQL Server 2017 document (
> >>>
> >>>
> >>
> https://docs.microsoft.com/en-us/sql/relational-databases/tables/specify-computed-columns-in-a-table?view=sql-server-2017
> >>> ),
> >>> "A
> >>> computed column is a virtual column that is not physically stored in
> the
> >>> table, unless the column is marked PERSISTED. A computed column
> >> expression
> >>> can use data from other columns to calculate a value for the column to
> >>> which it belongs. " I think we can also use introduce the PERSISTED
> >> keyword
> >>> for computed column to indicate that the field can be stored back to
> the
> >>> table, i.e. ts AS SYSTEMROWTIME() PERSISTED.
> >>>
> >>> 3) SOURCE / SINK / BOTH
> >>> GRANT/INVOKE sounds like a more standard option than adding a property
> to
> >>> CREATE TABLE to manage the ACL/permission. The ACL can be stored
> >> somewhere
> >>> in a database, and allow/disallow access to a dynamic table depending
> on
> >>> whether it's a "INSERT INTO" or "SELECT".
> >>>
> >>> I can volunteer to put the discussion as a FLIP.  I can try to
> summarize
> >>> the current discussion, and share edit permission with you to
> collaborate
> >>> on the documents. After we finalized the doc, we can publish it as a
> >> FLIP.
> >>> What do you think?
> >>>
> >>> Shuyi
> >>>
> >>>
> >>>
> >>> On Tue, Dec 11, 2018 at 9:13 AM Timo Walther <[hidden email]>
> wrote:
> >>>
> >>>> Hi all,
> >>>>
> >>>> thanks for summarizing the discussion @Shuyi. I think we need to
> >> include
> >>>> the "table update mode" problem as it might not be changed easily in
> >> the
> >>>> future. Regarding "support row/map/array data type", I don't see a
> >>>> problem why we should not support them now as the data types are
> >> already
> >>>> included in the runtime. The "support custom timestamp extractor" is
> >>>> solved by the computed columns approach. The "custom watermark
> >> strategy"
> >>>> can be added by supplying a class name as paramter in my opinion.
> >>>>
> >>>> Regarding the comments of Lin and Jark:
> >>>>
> >>>> @Lin: Instantiating a TableSource/Sink should not cost much, but we
> >>>> should not mix catalog discussion and DDL at this point.
> >>>>
> >>>> 4) Event-Time Attributes and Watermarks
> >>>> 4.b) Regarding `ts AS SYSTEMROWTIME()` and Lin's comment about "will
> >>>> violate the rule": there is no explicit rule of doing so. Computed
> >>>> column are also not standard compliant, if we can use information that
> >>>> is encoded in constraints we should use it. Adding more and more
> >>>> top-level properties makes the interaction with connectors more
> >>>> difficult. An additional HEADER keyword sounds too connector-specific
> >>>> and also not SQL compliant to me.
> >>>>
> >>>> 3) SOURCE / SINK / BOTH
> >>>> GRANT/INVOKE are mutating an existing table, right? In my opinion,
> >>>> independent of SQL databases but focusing on Flink user requirements,
> a
> >>>> CREATE TABLE statement should be an immutable definition of a
> >> connection
> >>>> to an external system.
> >>>>
> >>>> 7) Table Update Mode
> >>>> As far as I can see, the only thing missing for enabling all table
> >> modes
> >>>> is the declaration of a change flag. We could introduce a new keyword
> >>>> here similar to WATERMARK:
> >>>>
> >>>> CREATE TABLE output_kafka_t1(
> >>>>     id bigint,
> >>>>     msg varchar,
> >>>>     CHANGE_FLAG FOR isRetraction
> >>>> ) WITH (
> >>>>     type=kafka
> >>>>     ,...
> >>>> );
> >>>>
> >>>> CREATE TABLE output_kafka_t1(
> >>>>     CHANGE_FLAG FOR isUpsert
> >>>>     id bigint,
> >>>>     msg varchar,
> >>>>     PRIMARY_KEY(id)
> >>>> ) WITH (
> >>>>     type=kafka
> >>>>     ,...
> >>>> );
> >>>>
> >>>> What do you think?
> >>>>
> >>>> @Jark: We should definitely stage the discussions and mention the
> >>>> opinions and advantages/disadvantages that have been proposed already
> >> in
> >>>> the FLIP.
> >>>>
> >>>> Regards,
> >>>> Timo
> >>>>
> >>>> Am 10.12.18 um 08:10 schrieb Jark Wu:
> >>>>> Hi all,
> >>>>>
> >>>>> It's great to see we have an agreement on MVP.
> >>>>>
> >>>>> 4.b) Ingesting and writing timestamps to systems.
> >>>>> I would treat the field as a physical column not a virtual column. If
> >>> we
> >>>>> treat it as computed column, it will be confused that the behavior is
> >>>>> different when it is a source or sink.
> >>>>> When it is a physical column, the behavior could be unified. Then the
> >>>>> problem is how to mapping from the field to kafka message timestamp?
> >>>>> One is Lin proposed above and is also used in KSQL[1]. Another idea
> >> is
> >>>>> introducing a HEADER column which strictly map by name to the fields
> >> in
> >>>>> message header.
> >>>>> For example,
> >>>>>
> >>>>> CREATE TABLE output_kafka_t1(
> >>>>>     id bigint,
> >>>>>     ts timestamp HEADER,
> >>>>>     msg varchar
> >>>>> ) WITH (
> >>>>>     type=kafka
> >>>>>     ,...
> >>>>> );
> >>>>>
> >>>>> This is used in Alibaba but not included in the DDL draft. It will
> >>>> further
> >>>>> extend the SQL syntax, which is we should be cautious about. What do
> >>> you
> >>>>> think about this two solutions?
> >>>>>
> >>>>> 4.d) Custom watermark strategies:
> >>>>> @Timo,  I don't have a strong opinion on this.
> >>>>>
> >>>>> 3) SOURCE/SINK/BOTH
> >>>>> Agree with Lin, GRANT/INVOKE [SELECT|UPDATE] ON TABLE is a clean and
> >>>>> standard way to manage the permission, which is also adopted by
> >> HIVE[2]
> >>>> and
> >>>>> many databases.
> >>>>>
> >>>>> [1]:
> >>> https://docs.confluent.io/current/ksql/docs/tutorials/examples.html
> >>>>> [2]:
> >>>>>
> >>
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=45876173#Hivedeprecatedauthorizationmode/LegacyMode-Grant/RevokePrivileges
> >>>>> @Timo, it's great if someone can conclude the discussion and
> >> summarize
> >>>> into
> >>>>> a FLIP.
> >>>>> @Shuyi, Thanks a lot for putting it all together. The google doc
> >> looks
> >>>> good
> >>>>> to me, and I left some minor comments there.
> >>>>>
> >>>>> Regarding to the FLIP, I have some suggestions:
> >>>>> 1. The FLIP can contain MILESTONE1 and FUTURE WORKS.
> >>>>> 2. The MILESTONE1 is the MVP. It describes the MVP DDL syntax.
> >>>>> 3. Separate FUTURE WORKS into two parts: UNDER DISCUSSION and
> >> ADOPTED.
> >>> We
> >>>>> can derive MILESTONE2 from this easily when it is ready.
> >>>>>
> >>>>> I summarized the Future Works based on Shuyi's work:
> >>>>>
> >>>>> Adopted: (Should detailed described here...)
> >>>>> 1. support data type nullability and precision.
> >>>>> 2. comment on table and columns.
> >>>>>
> >>>>> Under Discussion: (Should briefly describe some options...)
> >>>>> 1. Ingesting and writing timestamps to systems.
> >>>>> 2. support custom watermark strategy.
> >>>>> 3. support table update mode
> >>>>> 4. support row/map/array data type
> >>>>> 5. support schema derivation
> >>>>> 6. support system versioned temporal table
> >>>>> 7. support table index
> >>>>>
> >>>>> We can continue the further discussion here, also can separate to an
> >>>> other
> >>>>> DISCUSS topic if it is a sophisticated problem such as Table Update
> >>> Mode,
> >>>>> Temporal Table.
> >>>>>
> >>>>> Best,
> >>>>> Jark
> >>>>>
> >>>>> On Mon, 10 Dec 2018 at 11:54, Lin Li <[hidden email]> wrote:
> >>>>>
> >>>>>> hi all,
> >>>>>> Thanks for your valuable input!
> >>>>>>
> >>>>>> 4) Event-Time Attributes and Watermarks:
> >>>>>> 4.b) @Fabian As you mentioned using a computed columns `ts AS
> >>>>>> SYSTEMROWTIME()`
> >>>>>> for writing out to kafka table sink will violate the rule that
> >>> computed
> >>>>>> fields are not emitted.
> >>>>>> Since the timestamp column in kafka's header area is a specific
> >>>>>> materialization protocol,
> >>>>>> why don't we treat it as an connector property? For an example:
> >>>>>> ```
> >>>>>> CREATE TABLE output_kafka_t1(
> >>>>>>     id bigint,
> >>>>>>     ts timestamp,
> >>>>>>     msg varchar
> >>>>>> ) WITH (
> >>>>>>     type=kafka,
> >>>>>>     header.timestamp=ts
> >>>>>>     ,...
> >>>>>> );
> >>>>>> ```
> >>>>>>
> >>>>>> 4d) For custom watermark strategies
> >>>>>> @Fabian Agree with you that opening another topic about this feature
> >>>> later.
> >>>>>> 3) SOURCE / SINK / BOTH
> >>>>>> I think the permissions and availabilities are two separately
> >> things,
> >>>>>> permissions
> >>>>>> can be managed well by using GRANT/INVOKE(you can call it DCL)
> >>> solutions
> >>>>>> which
> >>>>>> commonly used in different DBs. The permission part can be an new
> >>> topic
> >>>> for
> >>>>>> later discussion, what do you think?
> >>>>>>
> >>>>>> For the availabilities, @Fabian @Timo  I've another question,
> >>>>>> does instantiate a TableSource/Sink cost much or has some other
> >>>> downsides?
> >>>>>> IMO, create a new source/sink object via the construct seems not
> >>> costly.
> >>>>>> When receiving a DDL we should associate it with the catalog object
> >>>>>> (reusing an existence or create a new one).
> >>>>>> Am I lost something important?
> >>>>>>
> >>>>>> 5. Schema declaration:
> >>>>>> @Timo  yes, your concern about the user convenience is very
> >> important.
> >>>> But
> >>>>>> I haven't seen a clear way to solve this so far.
> >>>>>> Do we put it later and wait for more inputs from the community?
> >>>>>>
> >>>>>> Shuyi Chen <[hidden email]> 于2018年12月8日周六 下午4:27写道：
> >>>>>>
> >>>>>>> Hi all,
> >>>>>>>
> >>>>>>> Thanks a lot for the great discussion. I think we can continue the
> >>>>>>> discussion here while carving out a MVP so that the community can
> >>> start
> >>>>>>> working on. Based on the discussion so far, I try to summarize what
> >>> we
> >>>>>> will
> >>>>>>> do for the MVP:
> >>>>>>>
> >>>>>>> MVP
> >>>>>>>
> >>>>>>>      1. support CREATE TABLE
> >>>>>>>      2. support exisiting data type in Flink SQL, ignore
> nullability
> >>> and
> >>>>>>>      precision
> >>>>>>>      3. support table comments and column comments
> >>>>>>>      4. support table constraint PRIMARY KEY and UNIQUE
> >>>>>>>      5. support table properties using key-value pairs
> >>>>>>>      6. support partitioned by
> >>>>>>>      7. support computed column
> >>>>>>>      8. support from-field and from-source timestamp extractors
> >>>>>>>      9. support PERIODIC-ASCENDING, PERIODIC-BOUNDED, FROM-SOURCE
> >>>> watermark
> >>>>>>>      strategies.
> >>>>>>>      10. support a table property to allow explicit enforcement of
> >>>>>>>      read/write(source/sink) permission of a table
> >>>>>>>
> >>>>>>> I try to put up the DDL grammar (
> >>>>>>>
> >>>>>>>
> >>
> https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit?usp=sharing
> >>>>>>> )
> >>>>>>> based on the MVP features above and the previous design docs.
> >> Please
> >>>>>> take a
> >>>>>>> look and comment on it.
> >>>>>>>
> >>>>>>>
> >>>>>>> Also, I summarize the future Improvement on CREATE TABLE as the
> >>>>>> followings:
> >>>>>>>      1. support table update mode
> >>>>>>>      2. support data type nullability and precision
> >>>>>>>      3. support row/map/array data type
> >>>>>>>      4. support custom timestamp extractor and watermark strategy
> >>>>>>>      5. support schema derivation
> >>>>>>>      6. support system versioned temporal table
> >>>>>>>      7. support table index
> >>>>>>>
> >>>>>>> I suggest we first agree on the MVP feature list and the MVP
> >> grammar.
> >>>> And
> >>>>>>> then we can either continue the discussion of the future
> >> improvements
> >>>>>> here,
> >>>>>>> or create separate JIRAs for each item and discuss further in the
> >>> JIRA.
> >>>>>>> What do you guys think?
> >>>>>>>
> >>>>>>> Shuyi
> >>>>>>>
> >>>>>>> On Fri, Dec 7, 2018 at 7:54 AM Timo Walther <[hidden email]>
> >>>> wrote:
> >>>>>>>> Hi all,
> >>>>>>>>
> >>>>>>>> I think we are making good progress. Thanks for all the feedback
> >> so
> >>>>>> far.
> >>>>>>>> 3. Sources/Sinks:
> >>>>>>>> It seems that I can not find supporters for explicit SOURCE/SINK
> >>>>>>>> declaration so I'm fine with not using those keywords.
> >>>>>>>> @Fabian: Maybe we don't haven have to change the TableFactory
> >>>> interface
> >>>>>>>> but just provide some helper functions in the TableFactoryService.
> >>>> This
> >>>>>>>> would solve the availability problem, but the permission problem
> >>> would
> >>>>>>>> still not be solved. If you are fine with it, we could introduce a
> >>>>>>>> property instead?
> >>>>>>>>
> >>>>>>>> 5. Schema declaration:
> >>>>>>>> @Lin: We should find an agreement on this as it requires changes
> >> to
> >>>> the
> >>>>>>>> TableFactory interface. We should minimize changes to this
> >> interface
> >>>>>>>> because it is user-facing. Especially, if format schema and table
> >>>>>> schema
> >>>>>>>> differ, the need for such a functionality is very important. Our
> >>> goal
> >>>>>> is
> >>>>>>>> to connect to existing infrastructure. For example, if we are
> >> using
> >>>>>> Avro
> >>>>>>>> and the existing Avro format has enums but Flink SQL does not
> >>> support
> >>>>>>>> enums, it would be helpful to let the Avro format derive a table
> >>>>>> schema.
> >>>>>>>> Otherwise your need to declare both schemas which leads to CREATE
> >>>> TABLE
> >>>>>>>> statements of 400 lines+.
> >>>>>>>> I think the mentioned query:
> >>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> >>>>>>>> format.schema-file = "/my/avrofile.avsc")
> >>>>>>>> is fine and should only be valid if the schema contains no
> >>>> non-computed
> >>>>>>>> columns.
> >>>>>>>>
> >>>>>>>> 7. Table Update Mode:
> >>>>>>>> After thinking about it again, I agree. The mode of the sinks can
> >> be
> >>>>>>>> derived from the query and the existence of a PRIMARY KEY
> >>> declaration.
> >>>>>>>> But Fabian raised a very good point. How do we deal with sources?
> >>>> Shall
> >>>>>>>> we introduce a new keywords similar to WATERMARKS such that a
> >>>>>>>> upsert/retract flag is not part of the visible schema?
> >>>>>>>>
> >>>>>>>> 4a. How to mark a field as attribute?
> >>>>>>>> @Jark: Thanks for the explanation of the WATERMARK clause
> >> semantics.
> >>>>>>>> This is a nice way of marking existing fields. This sounds good to
> >>> me.
> >>>>>>>> 4c) WATERMARK as constraint
> >>>>>>>> I'm fine with leaving the WATERMARK clause in the schema
> >> definition.
> >>>>>>>> 4d) Custom watermark strategies:
> >>>>>>>> I would already think about custom watermark strategies as the
> >>> current
> >>>>>>>> descriptor design already supports this. ScalarFunction's don't
> >> work
> >>>> as
> >>>>>>>> a PeriodicWatermarkAssigner has different semantics. Why not
> >> simply
> >>>>>>>> entering the a full class name here as it is done in the current
> >>>>>> design?
> >>>>>>>> 4.b) Ingesting and writing timestamps to systems (like Kafka)
> >>>>>>>> @Fabian: Yes, your suggestion sounds good to me. This behavior
> >> would
> >>>> be
> >>>>>>>> similar to our current `timestamps: from-source` design.
> >>>>>>>>
> >>>>>>>> Once our discussion has found a conclusion, I would like to
> >>> volunteer
> >>>>>>>> and summarize the outcome of this mailing thread. It nicely aligns
> >>>> with
> >>>>>>>> the update work on the connector improvements document (that I
> >>> wanted
> >>>>>> to
> >>>>>>>> do anyway) and the ongoing external catalog discussion.
> >>> Furthermore, I
> >>>>>>>> would also want to propose how to change existing interfaces by
> >>>> keeping
> >>>>>>>> the DDL, connector improvements, and external catalog support in
> >>> mind.
> >>>>>>>> Would that be ok for you?
> >>>>>>>>
> >>>>>>>> Thanks,
> >>>>>>>> Timo
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> Am 07.12.18 um 14:48 schrieb Fabian Hueske:
> >>>>>>>>> Hi all,
> >>>>>>>>>
> >>>>>>>>> Thanks for the discussion.
> >>>>>>>>> I'd like to share my point of view as well.
> >>>>>>>>>
> >>>>>>>>> 4) Event-Time Attributes and Watermarks:
> >>>>>>>>> 4.a) I agree with Lin and Jark's proposal. Declaring a watermark
> >> on
> >>>>>> an
> >>>>>>>>> attribute declares it as an event-time attribute.
> >>>>>>>>> 4.b) Ingesting and writing timestamps to systems (like Kafka). We
> >>>>>> could
> >>>>>>>> use
> >>>>>>>>> a special function like (ts AS SYSTEMROWTIME()). This function
> >> will
> >>>>>>>>> indicate that we read the timestamp directly from the system (and
> >>> not
> >>>>>>> the
> >>>>>>>>> data). We can also write the field back to the system when
> >> emitting
> >>>>>> the
> >>>>>>>>> table (violating the rule that computed fields are not emitted).
> >>>>>>>>> 4c) I would treat WATERMARK similar to a PRIMARY KEY or UNIQUE
> >> KEY
> >>>>>>>>> constraint and therefore keep it in the schema definition.
> >>>>>>>>> 4d) For custom watermark strategies, a simple expressions or
> >>>>>>>>> ScalarFunctions won't be sufficient. Sophisticated approaches
> >> could
> >>>>>>>> collect
> >>>>>>>>> histograms, etc. But I think we can leave that out for later.
> >>>>>>>>>
> >>>>>>>>> 3) SOURCE / SINK / BOTH
> >>>>>>>>> As you said, there are two things to consider here: permission
> >> and
> >>>>>>>>> availability of a TableSource/TableSink.
> >>>>>>>>> I think that neither should be a reason to add a keyword at such
> >> a
> >>>>>>>>> sensitive position.
> >>>>>>>>> However, I also see Timo's point that it would be good to know
> >>>>>> up-front
> >>>>>>>> how
> >>>>>>>>> a table can be used without trying to instantiate a
> >>> TableSource/Sink
> >>>>>>> for
> >>>>>>>> a
> >>>>>>>>> query.
> >>>>>>>>> Maybe we can extend the TableFactory such that it provides
> >>>>>> information
> >>>>>>>>> about which sources/sinks it can provide.
> >>>>>>>>>
> >>>>>>>>> 7. Table Update Mode
> >>>>>>>>> Something that we definitely need to consider is how tables are
> >>>>>>> ingested,
> >>>>>>>>> i.e., append, retract or upsert.
> >>>>>>>>> Especially, since upsert and retraction need a meta-data column
> >>> that
> >>>>>>>>> indicates whether an event is an insert (or upsert) or a delete
> >>>>>> change.
> >>>>>>>>> This column needs to be identified somehow, most likely as part
> >> of
> >>>>>> the
> >>>>>>>>> input format. Ideally, this column should not be part of the
> >> table
> >>>>>>> schema
> >>>>>>>>> (as it would be always true).
> >>>>>>>>> Emitting tables is not so much of an issue as the properties of
> >> the
> >>>>>>> table
> >>>>>>>>> tell use what to do (append-only/update, unique key y/n).
> >>>>>>>>>
> >>>>>>>>> Best,
> >>>>>>>>> Fabian
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Am Fr., 7. Dez. 2018 um 10:39 Uhr schrieb Jark Wu <
> >>> [hidden email]
> >>>>>>> :
> >>>>>>>>>> Hi Timo,
> >>>>>>>>>>
> >>>>>>>>>> Thanks for your quickly feedback! Here are some of my thoughts:
> >>>>>>>>>>
> >>>>>>>>>> Append, upserts, retract mode on sinks is also a very complex
> >>>>>>> problem. I
> >>>>>>>>>> think append/upserts/retract is the ability of a table, user do
> >>> not
> >>>>>>>> need to
> >>>>>>>>>> specify a table is used for append or retraction or upsert. The
> >>>>>> query
> >>>>>>>> can
> >>>>>>>>>> choose which mode the sink is. If an unbounded groupby is
> >> inserted
> >>>>>>> into
> >>>>>>>> an
> >>>>>>>>>> append sink (the sink only implements/supports append), an
> >>> exception
> >>>>>>>> can be
> >>>>>>>>>> thrown. A more complex problem is, if we want to write
> >>>>>>>> retractions/upserts
> >>>>>>>>>> to Kafka, how to encode the change flag (add or retract/delete)
> >> on
> >>>>>> the
> >>>>>>>>>> table? Maybe we should propose some protocal for the change flag
> >>>>>>>> encoding,
> >>>>>>>>>> but I don't have a clear idea about this right now.
> >>>>>>>>>>
> >>>>>>>>>> 3. Sources/Sinks: The source/sink tag is similar to the
> >>>>>>>>>> append/upsert/retract problem. Besides source/sink, actully we
> >>> have
> >>>>>>>> stream
> >>>>>>>>>> source, stream sink, batch source, batch sink, and the stream
> >> sink
> >>>>>>> also
> >>>>>>>>>> include append/upsert/retract three modes. Should we put all the
> >>>>>> tags
> >>>>>>> on
> >>>>>>>>>> the CREATE TABLE? IMO, the table's ability is defined by the
> >> table
> >>>>>>>> itself,
> >>>>>>>>>> user do not need to specify it. If it is only a readable table,
> >> an
> >>>>>>>>>> exception can be thrown when write to it. As the source/sink tag
> >>> can
> >>>>>>> be
> >>>>>>>>>> omitted in CREATE TABLE, could we skip it and only support
> >> CREATE
> >>>>>>> TABLE
> >>>>>>>> in
> >>>>>>>>>> the first version, and add it back in the future when we really
> >>> need
> >>>>>>>> it? It
> >>>>>>>>>> keeps API compatible and make sure the MVP is what we consider
> >>>>>>> clearly.
> >>>>>>>>>> 4a. How to mark a field as attribute?
> >>>>>>>>>> The watermark definition includes two parts: use which field as
> >>> time
> >>>>>>>>>> attribute and use what generate strategy.
> >>>>>>>>>> When we want to mark `ts` field as attribute: WATERMARK FOR `ts`
> >>> AS
> >>>>>>>> OFFSET
> >>>>>>>>>> '5' SECOND.
> >>>>>>>>>> If we have a POJO{id, user, ts} field named "pojo", we can mark
> >> it
> >>>>>>> like
> >>>>>>>>>> this: WATERMARK FOR pojo.ts AS OFFSET '5' SECOND
> >>>>>>>>>>
> >>>>>>>>>> 4b. timestamp write to Kafka message header
> >>>>>>>>>> Even though we can define multiple time attribute on a table,
> >> only
> >>>>>> one
> >>>>>>>> time
> >>>>>>>>>> attribute can be actived/used in a query (in a stream). When we
> >>>>>> enable
> >>>>>>>>>> `writeTiemstamp`, the only attribute actived in the stream will
> >> be
> >>>>>>>> write to
> >>>>>>>>>> Kafka message header. What I mean the timestmap in StreamRecord
> >> is
> >>>>>> the
> >>>>>>>> time
> >>>>>>>>>> attribute in the stream.
> >>>>>>>>>>
> >>>>>>>>>> 4c. Yes. We introduced the WATERMARK keyword similar to the
> >> INDEX,
> >>>>>>>> PRIMARY
> >>>>>>>>>> KEY keywords.
> >>>>>>>>>>
> >>>>>>>>>> @Timo, Do you have any other advice or questions on the
> >> watermark
> >>>>>>>> syntax ?
> >>>>>>>>>> For example, the builtin strategy name: "BOUNDED WITH OFFSET" VS
> >>>>>>>> "OFFSET"
> >>>>>>>>>> VS ...
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> Cheers,
> >>>>>>>>>> Jark
> >>>>>>>>>>
> >>>>>>>>>> On Fri, 7 Dec 2018 at 17:13, Lin Li <[hidden email]>
> >>> wrote:
> >>>>>>>>>>> Hi Timo,
> >>>>>>>>>>> Thanks for your feedback, here's some thoughts of mine:
> >>>>>>>>>>>
> >>>>>>>>>>> 3. Sources/Sinks:
> >>>>>>>>>>> "Let's assume an interactive CLI session, people should be able
> >>> to
> >>>>>>> list
> >>>>>>>>>> all
> >>>>>>>>>>> source table and sink tables to know upfront if they can use an
> >>>>>>> INSERT
> >>>>>>>>>> INTO
> >>>>>>>>>>> here or not."
> >>>>>>>>>>> This requirement can be simply resolved by a document that list
> >>> all
> >>>>>>>>>>> supported source/sink/both connectors and the sql-client can
> >>>>>> perform
> >>>>>>> a
> >>>>>>>>>>> quick check. It's only an implementation choice, not necessary
> >>> for
> >>>>>>> the
> >>>>>>>>>>> syntax.
> >>>>>>>>>>> For connector implementation, a connector may implement one or
> >>> some
> >>>>>>> or
> >>>>>>>>>> all
> >>>>>>>>>>> of the [Stream|Batch]Source/[Stream|Batch]Sink traits, we can
> >>>>>> derive
> >>>>>>>> the
> >>>>>>>>>>> availability for any give query without the SOURCE/SINk
> >> keywords
> >>> or
> >>>>>>>>>>> specific table properties in WITH clause.
> >>>>>>>>>>> Since there's still indeterminacy, shall we skip these two
> >>> keywords
> >>>>>>> for
> >>>>>>>>>> the
> >>>>>>>>>>> MVP DDL? We can make further discussion after users' feedback.
> >>>>>>>>>>>
> >>>>>>>>>>> 6. Partitioning and keys
> >>>>>>>>>>> Agree with you that raise the priority of table constraint and
> >>>>>>>>>> partitioned
> >>>>>>>>>>> table support for better connectivity to Hive and Kafka. I'll
> >> add
> >>>>>>>>>>> partitioned table syntax(compatible to hive) into the DDL Draft
> >>> doc
> >>>>>>>>>>> later[1].
> >>>>>>>>>>>
> >>>>>>>>>>> 5. Schema declaration
> >>>>>>>>>>> "if users want to declare computed columns they have a "schema"
> >>>>>>>>>> constraints
> >>>>>>>>>>> but without columns
> >>>>>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> >>>>>>>>>>> format.schema-file = "/my/avrofile.avsc") "
> >>>>>>>>>>>
> >>>>>>>>>>>    From the point of my view, this ddl is invalid because the
> >>>> primary
> >>>>>>> key
> >>>>>>>>>>> constraint already references two columns but types unseen.
> >>>>>>>>>>> And Xuefu pointed a important matching problem, so let's put
> >>> schema
> >>>>>>>>>>> derivation as a follow-up extension ?
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>> Timo Walther <[hidden email]> 于2018年12月6日周四 下午6:05写道：
> >>>>>>>>>>>
> >>>>>>>>>>>> Hi everyone,
> >>>>>>>>>>>>
> >>>>>>>>>>>> great to have such a lively discussion. My next batch of
> >>> feedback:
> >>>>>>>>>>>> @Jark: We don't need to align the descriptor approach with
> >> SQL.
> >>>>>> I'm
> >>>>>>>>>> open
> >>>>>>>>>>>> for different approaches as long as we can serve a broad set
> >> of
> >>>>>> use
> >>>>>>>>>>>> cases and systems. The descriptor approach was a first attempt
> >>> to
> >>>>>>>> cover
> >>>>>>>>>>>> all aspects and connector/format characteristics. Just another
> >>>>>>>> example,
> >>>>>>>>>>>> that is missing in the DDL design: How can a user decide if
> >>>>>> append,
> >>>>>>>>>>>> retraction, or upserts should be used to sink data into the
> >>> target
> >>>>>>>>>>>> system? Do we want to define all these improtant properties in
> >>> the
> >>>>>>> big
> >>>>>>>>>>>> WITH property map? If yes, we are already close to the
> >>> descriptor
> >>>>>>>>>>>> approach. Regarding the "standard way", most DDL languages
> >> have
> >>>>>> very
> >>>>>>>>>>>> custom syntax so there is not a real "standard".
> >>>>>>>>>>>>
> >>>>>>>>>>>> 3. Sources/Sinks: @Lin: If a table has both read/write access
> >> it
> >>>>>> can
> >>>>>>>> be
> >>>>>>>>>>>> created using a regular CREATE TABLE (omitting a specific
> >>>>>>> source/sink)
> >>>>>>>>>>>> declaration. Regarding the transition from source/sink to
> >> both,
> >>>>>> yes
> >>>>>>> we
> >>>>>>>>>>>> would need to update the a DDL and catalogs. But is this a
> >>>>>> problem?
> >>>>>>>> One
> >>>>>>>>>>>> also needs to add new queries that use the tables. @Xuefu: It
> >> is
> >>>>>> not
> >>>>>>>>>>>> only about security aspects. Especially for streaming use
> >> cases,
> >>>>>> not
> >>>>>>>>>>>> every connector can be used as a source easily. For example, a
> >>>>>> JDBC
> >>>>>>>>>> sink
> >>>>>>>>>>>> is easier than a JDBC source. Let's assume an interactive CLI
> >>>>>>> session,
> >>>>>>>>>>>> people should be able to list all source table and sink tables
> >>> to
> >>>>>>> know
> >>>>>>>>>>>> upfront if they can use an INSERT INTO here or not.
> >>>>>>>>>>>>
> >>>>>>>>>>>> 6. Partitioning and keys: @Lin: I would like to include this
> >> in
> >>>>>> the
> >>>>>>>>>>>> design given that Hive integration and Kafka key support are
> >> in
> >>>>>> the
> >>>>>>>>>>>> making/are on our roadmap for this release.
> >>>>>>>>>>>>
> >>>>>>>>>>>> 5. Schema declaration: @Lin: You are right it is not
> >>> conflicting.
> >>>>>> I
> >>>>>>>>>> just
> >>>>>>>>>>>> wanted to raise the point because if users want to declare
> >>>>>> computed
> >>>>>>>>>>>> columns they have a "schema" constraints but without columns.
> >>> Are
> >>>>>> we
> >>>>>>>> ok
> >>>>>>>>>>>> with a syntax like ...
> >>>>>>>>>>>> CREATE TABLE (PRIMARY_KEY(a, c)) WITH (format.type = avro,
> >>>>>>>>>>>> format.schema-file = "/my/avrofile.avsc") ?
> >>>>>>>>>>>> @Xuefu: Yes, you are right that an external schema might not
> >>>>>> excatly
> >>>>>>>>>>>> match but this is true for both directions:
> >>>>>>>>>>>> table schema "derives" format schema and format schema
> >> "derives"
> >>>>>>> table
> >>>>>>>>>>>> schema.
> >>>>>>>>>>>>
> >>>>>>>>>>>> 7. Hive compatibility: @Xuefu: I agree that Hive is popular
> >> but
> >>> we
> >>>>>>>>>>>> should not just adopt everything from Hive as there syntax is
> >>> very
> >>>>>>>>>>>> batch-specific. We should come up with a superset of
> >> historical
> >>>>>> and
> >>>>>>>>>>>> future requirements. Supporting Hive queries can be an
> >>>>>> intermediate
> >>>>>>>>>>>> layer on top of Flink's DDL.
> >>>>>>>>>>>>
> >>>>>>>>>>>> 4. Time attributes: @Lin: I'm fine with changing the
> >>>>>>>> TimestampExtractor
> >>>>>>>>>>>> interface as this is also important for better separation of
> >>>>>>> connector
> >>>>>>>>>>>> and table module [1]. However, I'm wondering about watermark
> >>>>>>>>>> generation.
> >>>>>>>>>>>> 4a. timestamps are in the schema twice:
> >>>>>>>>>>>> @Jark: "existing field is Long/Timestamp, we can just use it
> >> as
> >>>>>>>>>>>> rowtime": yes, but we need to mark a field as such an
> >> attribute.
> >>>>>> How
> >>>>>>>>>>>> does the syntax for marking look like? Also in case of
> >>> timestamps
> >>>>>>> that
> >>>>>>>>>>>> are nested in the schema?
> >>>>>>>>>>>>
> >>>>>>>>>>>> 4b. how can we write out a timestamp into the message header?:
> >>>>>>>>>>>> I agree to simply ignore computed columns when writing out.
> >> This
> >>>>>> is
> >>>>>>>>>> like
> >>>>>>>>>>>> 'field-change: add' that I mentioned in the improvements
> >>> document.
> >>>>>>>>>>>> @Jark: "then the timestmap in StreamRecord will be write to
> >>> Kafka
> >>>>>>>>>>>> message header": Unfortunately, there is no timestamp in the
> >>>>>> stream
> >>>>>>>>>>>> record. Additionally, multiple time attributes can be in a
> >>> schema.
> >>>>>>> So
> >>>>>>>>>> we
> >>>>>>>>>>>> need a constraint that tells the sink which column to use
> >>>>>> (possibly
> >>>>>>>>>>>> computed as well)?
> >>>>>>>>>>>>
> >>>>>>>>>>>> 4c. separate all time attribute concerns into a special clause
> >>>>>> next
> >>>>>>> to
> >>>>>>>>>>>> the regular schema?
> >>>>>>>>>>>> @Jark: I don't have a strong opinion on this. I just have the
> >>>>>>> feeling
> >>>>>>>>>>>> that the "schema part" becomes quite messy because the actual
> >>>>>> schema
> >>>>>>>>>>>> with types and fields is accompanied by so much metadata about
> >>>>>>>>>>>> timestamps, watermarks, keys,... and we would need to
> >> introduce
> >>> a
> >>>>>>> new
> >>>>>>>>>>>> WATERMARK keyword within a schema that was close to standard
> >> up
> >>> to
> >>>>>>>> this
> >>>>>>>>>>>> point.
> >>>>>>>>>>>>
> >>>>>>>>>>>> Thanks everyone,
> >>>>>>>>>>>> Timo
> >>>>>>>>>>>>
> >>>>>>>>>>>> [1] https://issues.apache.org/jira/browse/FLINK-9461
> >>>>>>>>>>>>
> >>>>>>>>>>>>
> >>>>>>>>>>>>
> >>>>>>>>>>>> Am 06.12.18 um 07:08 schrieb Jark Wu:
> >>>>>>>>>>>>> Hi Timo,
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Thank you for the valuable feedbacks.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> First of all, I think we don't need to align the SQL
> >>>>>> functionality
> >>>>>>> to
> >>>>>>>>>>>>> Descriptor. Because SQL is a more standard API, we should be
> >> as
> >>>>>>>>>>> cautious
> >>>>>>>>>>>> as
> >>>>>>>>>>>>> possible to extend the SQL syntax. If something can be done
> >> in
> >>> a
> >>>>>>>>>>> standard
> >>>>>>>>>>>>> way, we shouldn't introduce something new.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> Here are some of my thoughts:
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> 1. Scope: Agree.
> >>>>>>>>>>>>> 2. Constraints: Agree.
> >>>>>>>>>>>>> 4. Time attributes:
> >>>>>>>>>>>>>       4a. timestamps are in the schema twice.
> >>>>>>>>>>>>>        If an existing field is Long/Timestamp, we can just
> use
> >>> it
> >>>>>> as
> >>>>>>>>>>>> rowtime,
> >>>>>>>>>>>>> no twice defined. If it is not a Long/Timestamp, we use
> >>> computed
> >>>>>>>>>> column
> >>>>>>>>>>>> to
> >>>>>>>>>>>>> get an expected timestamp column to be rowtime, is this what
> >>> you
> >>>>>>> mean
> >>>>>>>>>>>>> defined twice?  But I don't think it is a problem, but an
> >>>>>>> advantages,
> >>>>>>>>>>>>> because it is easy to use, user do not need to consider
> >> whether
> >>>>>> to
> >>>>>>>>>>>> "replace
> >>>>>>>>>>>>> the existing column" or "add a new column", he will not be
> >>>>>> confused
> >>>>>>>>>>>> what's
> >>>>>>>>>>>>> the real schema is, what's the index of rowtime in the
> >> schema?
> >>>>>>>>>>> Regarding
> >>>>>>>>>>>> to
> >>>>>>>>>>>>> the optimization, even if timestamps are in schema twice,
> >> when
> >>>>>> the
> >>>>>>>>>>>> original
> >>>>>>>>>>>>> timestamp is never used in query, then the projection
> >> pushdown
> >>>>>>>>>>>> optimization
> >>>>>>>>>>>>> can cut this field as early as possible, which is exactly the
> >>>>>> same
> >>>>>>> as
> >>>>>>>>>>>>> "replacing the existing column" in runtime.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>        4b. how can we write out a timestamp into the message
> >>>>>> header?
> >>>>>>>>>>>>>         That's a good point. I think computed column is just
> a
> >>>>>>> virtual
> >>>>>>>>>>>> column
> >>>>>>>>>>>>> on table which is only relative to reading. If we want to
> >> write
> >>>>>> to
> >>>>>>> a
> >>>>>>>>>>>> table
> >>>>>>>>>>>>> with computed column defined, we only need to provide the
> >>> columns
> >>>>>>>>>>> except
> >>>>>>>>>>>>> computed columns (see SQL Server [1]). The computed column is
> >>>>>>> ignored
> >>>>>>>>>>> in
> >>>>>>>>>>>>> the insert statement. Get back to the question, how can we
> >>> write
> >>>>>>> out
> >>>>>>>>>> a
> >>>>>>>>>>>>> timestamp into the message header? IMO, we can provide a
> >>>>>>>>>> configuration
> >>>>>>>>>>> to
> >>>>>>>>>>>>> support this, such as `kafka.writeTimestamp=true`, then the
> >>>>>>> timestmap
> >>>>>>>>>>> in
> >>>>>>>>>>>>> StreamRecord will be write to Kafka message header. What do
> >> you
> >>>>>>>>>> think?
> >>>>>>>>>>>>>         4c. separate all time attribute concerns into a
> >> special
> >>>>>>> clause
> >>>>>>>>>>> next
> >>>>>>>>>>>> to
> >>>>>>>>>>>>> the regular schema?
> >>>>>>>>>>>>>         Separating watermark into a special clause similar to
> >>>>>>>>>> PARTITIONED
> >>>>>>>>>>>> BY is
> >>>>>>>>>>>>> also a good idea. Conceptually, it's fine to put watermark in
> >>>>>>> schema
> >>>>>>>>>>> part
> >>>>>>>>>>>>> or out schema part. But if we want to support multiple
> >>> watermark
> >>>>>>>>>>>>> definition, maybe it would be better to put it in schema
> >> part.
> >>> It
> >>>>>>> is
> >>>>>>>>>>>>> similar to Index Definition that we can define several
> >> indexes
> >>>>>> on a
> >>>>>>>>>>> table
> >>>>>>>>>>>>> in schema part.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>         4d. How can people come up with a custom watermark
> >>>>>> strategy?
> >>>>>>>>>>>>>         In most cases, the built-in strategy can works good.
> >> If
> >>> we
> >>>>>>> need
> >>>>>>>>>> a
> >>>>>>>>>>>>> custom one, we can use a scalar function which restrict to
> >> only
> >>>>>>>>>> return
> >>>>>>>>>>> a
> >>>>>>>>>>>>> nullable Long, and use it in SQL like: WATERMARK for rowtime
> >> AS
> >>>>>>>>>>>>> watermarkUdf(a, b, c). The `watermarkUdf` is a user-defined
> >>>>>> scalar
> >>>>>>>>>>>> function
> >>>>>>>>>>>>> accepts 3 parameters and return a nullable Long which can be
> >>> used
> >>>>>>> as
> >>>>>>>>>>>>> punctuated watermark assigner. Another choice is
> >> implementing a
> >>>>>>> class
> >>>>>>>>>>>>> extending the
> >>>>>>>>>>>>>
> >> `org.apache.flink.table.sources.wmstrategies.WatermarkStrategy`
> >>>>>> and
> >>>>>>>>>> use
> >>>>>>>>>>>> it
> >>>>>>>>>>>>> in SQL: WATERMARK for rowtime AS
> >> 'com.my.MyWatermarkStrategy'.
> >>>>>> But
> >>>>>>> if
> >>>>>>>>>>>>> scalar function can cover the requirements here, I would
> >> prefer
> >>>>>> it
> >>>>>>>>>>> here,
> >>>>>>>>>>>>> because it keeps standard compliant. BTW, this feature is not
> >>> in
> >>>>>>> MVP,
> >>>>>>>>>>> we
> >>>>>>>>>>>>> can discuss it more depth in the future when we need it.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> 5. Schema declaration:
> >>>>>>>>>>>>> I like the proposal to omit the schema if we can get the
> >> schema
> >>>>>>> from
> >>>>>>>>>>>>> external storage or something schema file. Actually, we have
> >>>>>>> already
> >>>>>>>>>>>>> encountered this requirement in out company.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> +1 to @Xuefu that we should be as close as possible to Hive
> >>>>>> syntax
> >>>>>>>>>>> while
> >>>>>>>>>>>>> keeping SQL ANSI standard. This will make it more acceptable
> >>> and
> >>>>>>>>>> reduce
> >>>>>>>>>>>> the
> >>>>>>>>>>>>> learning cost for user.
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> [1]:
> >>>>>>>>>>>>>
> >>
> https://docs.microsoft.com/en-us/sql/relational-databases/partitions/create-partitioned-tables-and-indexes?view=sql-server-2017
> >>>>>>>>>>>>> Best,
> >>>>>>>>>>>>> Jark
> >>>>>>>>>>>>>
> >>>>>>>>>>>>> On Thu, 6 Dec 2018 at 12:09, Zhang, Xuefu <
> >>>>>> [hidden email]
> >>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>> Hi Timo/Shuyi/Lin,
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Thanks for the discussions. It seems that we are converging
> >> to
> >>>>>>>>>>> something
> >>>>>>>>>>>>>> meaningful. Here are some of my thoughts:
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 1. +1 on MVP DDL
> >>>>>>>>>>>>>> 3. Markers for source or sink seem more about permissions on
> >>>>>>> tables
> >>>>>>>>>>> that
> >>>>>>>>>>>>>> belong to a security component. Unless the table is created
> >>>>>>>>>>> differently
> >>>>>>>>>>>>>> based on source, sink, or both, it doesn't seem necessary to
> >>> use
> >>>>>>>>>> these
> >>>>>>>>>>>>>> keywords to enforce permissions.
> >>>>>>>>>>>>>> 5. It might be okay if schema declaration is always needed.
> >>>>>> While
> >>>>>>>>>>> there
> >>>>>>>>>>>>>> might be some duplication sometimes, it's not always true.
> >> For
> >>>>>>>>>>> example,
> >>>>>>>>>>>>>> external schema may not be exactly matching Flink schema.
> >> For
> >>>>>>>>>>> instance,
> >>>>>>>>>>>>>> data types. Even if so, perfect match is not required. For
> >>>>>>> instance,
> >>>>>>>>>>> the
> >>>>>>>>>>>>>> external schema file may evolve while table schema in Flink
> >>> may
> >>>>>>> stay
> >>>>>>>>>>>>>> unchanged. A responsible reader should be able to scan the
> >>> file
> >>>>>>>>>> based
> >>>>>>>>>>> on
> >>>>>>>>>>>>>> file schema and return the data based on table schema.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Other aspects:
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 7. Hive compatibility. Since Flink SQL will soon be able to
> >>>>>>> operate
> >>>>>>>>>> on
> >>>>>>>>>>>>>> Hive metadata and data, it's an add-on benefit if we can be
> >>>>>>>>>> compatible
> >>>>>>>>>>>> with
> >>>>>>>>>>>>>> Hive syntax/semantics while following ANSI standard. At
> >> least
> >>> we
> >>>>>>>>>>> should
> >>>>>>>>>>>> be
> >>>>>>>>>>>>>> as close as possible. Hive DDL can found at
> >>>>>>>>>>>>>>
> >> https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL
> >>>>>>>>>>>>>> Thanks,
> >>>>>>>>>>>>>> Xuefu
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>
> >>>>>> ------------------------------------------------------------------
> >>>>>>>>>>>>>> Sender:Lin Li <[hidden email]>
> >>>>>>>>>>>>>> Sent at:2018 Dec 6 (Thu) 10:49
> >>>>>>>>>>>>>> Recipient:dev <[hidden email]>
> >>>>>>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Hi Timo and Shuyi,
> >>>>>>>>>>>>>>       thanks for your feedback.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 1. Scope
> >>>>>>>>>>>>>> agree with you we should focus on the MVP DDL first.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 2. Constraints
> >>>>>>>>>>>>>> yes, this can be a follow-up issue.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 3. Sources/Sinks
> >>>>>>>>>>>>>> If a TABLE has both read/write access requirements, should
> >> we
> >>>>>>>>>> declare
> >>>>>>>>>>> it
> >>>>>>>>>>>>>> using
> >>>>>>>>>>>>>> `CREATE [SOURCE_SINK|BOTH] TABLE tableName ...` ? A further
> >>>>>>>>>> question,
> >>>>>>>>>>>> if a
> >>>>>>>>>>>>>> TABLE
> >>>>>>>>>>>>>> t1 firstly declared as read only (as a source table), then
> >> for
> >>>>>>> some
> >>>>>>>>>>> new
> >>>>>>>>>>>>>> requirements
> >>>>>>>>>>>>>> t1 will change to a sink table,  in this case we need
> >> updating
> >>>>>>> both
> >>>>>>>>>>> the
> >>>>>>>>>>>> DDL
> >>>>>>>>>>>>>> and catalogs.
> >>>>>>>>>>>>>> Further more, let's think about the BATCH query, update one
> >>>>>> table
> >>>>>>>>>>>> in-place
> >>>>>>>>>>>>>> can be a common case.
> >>>>>>>>>>>>>> e.g.,
> >>>>>>>>>>>>>> ```
> >>>>>>>>>>>>>> CREATE TABLE t1 (
> >>>>>>>>>>>>>>       col1 varchar,
> >>>>>>>>>>>>>>       col2 int,
> >>>>>>>>>>>>>>       col3 varchar
> >>>>>>>>>>>>>>       ...
> >>>>>>>>>>>>>> );
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> INSERT [OVERWRITE] TABLE t1
> >>>>>>>>>>>>>> AS
> >>>>>>>>>>>>>> SELECT
> >>>>>>>>>>>>>>       (some computing ...)
> >>>>>>>>>>>>>> FROM t1;
> >>>>>>>>>>>>>> ```
> >>>>>>>>>>>>>> So, let's forget these SOURCE/SINK keywords in DDL. For the
> >>>>>>>>>> validation
> >>>>>>>>>>>>>> purpose, we can find out other ways.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 4. Time attributes
> >>>>>>>>>>>>>> As Shuyi mentioned before, there exists an
> >>>>>>>>>>>>>>
> >>> `org.apache.flink.table.sources.tsextractors.TimestampExtractor`
> >>>>>>> for
> >>>>>>>>>>>> custom
> >>>>>>>>>>>>>> defined time attributes usage, but this expression based
> >> class
> >>>>>> is
> >>>>>>>>>> more
> >>>>>>>>>>>>>> friendly for table api not the SQL.
> >>>>>>>>>>>>>> ```
> >>>>>>>>>>>>>> /**
> >>>>>>>>>>>>>>       * Provides the an expression to extract the timestamp
> >>> for a
> >>>>>>>>>> rowtime
> >>>>>>>>>>>>>> attribute.
> >>>>>>>>>>>>>>       */
> >>>>>>>>>>>>>> abstract class TimestampExtractor extends
> >> FieldComputer[Long]
> >>>>>> with
> >>>>>>>>>>>>>> Serializable {
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>       /** Timestamp extractors compute the timestamp as
> Long.
> >>> */
> >>>>>>>>>>>>>>       override def getReturnType: TypeInformation[Long] =
> >>>>>>>>>>>>>> Types.LONG.asInstanceOf[TypeInformation[Long]]
> >>>>>>>>>>>>>> }
> >>>>>>>>>>>>>> ```
> >>>>>>>>>>>>>> BTW, I think both the Scalar function and the
> >>> TimestampExtractor
> >>>>>>> are
> >>>>>>>>>>>>>> expressing computing logic, the TimestampExtractor has no
> >> more
> >>>>>>>>>>>> advantage in
> >>>>>>>>>>>>>> SQL scenarios.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 6. Partitioning and keys
> >>>>>>>>>>>>>> Primary Key is included in Constraint part, and partitioned
> >>>>>> table
> >>>>>>>>>>>> support
> >>>>>>>>>>>>>> can be another topic later.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> 5. Schema declaration
> >>>>>>>>>>>>>> Agree with you that we can do better schema derivation for
> >>> user
> >>>>>>>>>>>>>> convenience, but this is not conflict with the syntax.
> >>>>>>>>>>>>>> Table properties can carry any useful informations both for
> >>> the
> >>>>>>>>>> users
> >>>>>>>>>>>> and
> >>>>>>>>>>>>>> the framework, I like your `contract name` proposal,
> >>>>>>>>>>>>>> e.g., `WITH (format.type = avro)`, the framework can
> >> recognize
> >>>>>>> some
> >>>>>>>>>>>>>> `contract name` like `format.type`, `connector.type` and
> >> etc.
> >>>>>>>>>>>>>> And also derive the table schema from an existing schema
> >> file
> >>>>>> can
> >>>>>>> be
> >>>>>>>>>>>> handy
> >>>>>>>>>>>>>> especially one with too many table columns.
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>> Lin
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>> Timo Walther <[hidden email]> 于2018年12月5日周三 下午10:40写道：
> >>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> Hi Jark and Shuyi,
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> thanks for pushing the DDL efforts forward. I agree that we
> >>>>>>> should
> >>>>>>>>>>> aim
> >>>>>>>>>>>>>>> to combine both Shuyi's design and your design.
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> Here are a couple of concerns that I think we should
> >> address
> >>> in
> >>>>>>> the
> >>>>>>>>>>>>>> design:
> >>>>>>>>>>>>>>> 1. Scope: Let's focuses on a MVP DDL for CREATE TABLE
> >>>>>> statements
> >>>>>>>>>>> first.
> >>>>>>>>>>>>>>> I think this topic has already enough potential for long
> >>>>>>>>>> discussions
> >>>>>>>>>>>> and
> >>>>>>>>>>>>>>> is very helpful for users. We can discuss CREATE VIEW and
> >>>>>> CREATE
> >>>>>>>>>>>>>>> FUNCTION afterwards as they are not related to each other.
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> 2. Constraints: I think we should consider things like
> >>>>>>> nullability,
> >>>>>>>>>>>>>>> VARCHAR length, and decimal scale and precision in the
> >> future
> >>>>>> as
> >>>>>>>>>> they
> >>>>>>>>>>>>>>> allow for nice optimizations. However, since both the
> >>>>>> translation
> >>>>>>>>>> and
> >>>>>>>>>>>>>>> runtime operators do not support those features. I would
> >> not
> >>>>>>>>>>> introduce
> >>>>>>>>>>>> a
> >>>>>>>>>>>>>>> arbitrary default value but omit those parameters for now.
> >>> This
> >>>>>>> can
> >>>>>>>>>>> be
> >>>>>>>>>>>> a
> >>>>>>>>>>>>>>> follow-up issue once the basic DDL has been merged.
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> 3. Sources/Sinks: We had a discussion about CREATE TABLE vs
> >>>>>>> CREATE
> >>>>>>>>>>>>>>> [SOURCE|SINK|] TABLE before. In my opinion we should allow
> >>> for
> >>>>>>>>>> these
> >>>>>>>>>>>>>>> explicit declaration because in most production scenarios,
> >>>>>> teams
> >>>>>>>>>> have
> >>>>>>>>>>>>>>> strict read/write access requirements. For example, a data
> >>>>>>> science
> >>>>>>>>>>> team
> >>>>>>>>>>>>>>> should only consume from a event Kafka topic but should not
> >>>>>>>>>>> accidently
> >>>>>>>>>>>>>>> write back to the single source of truth.
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> 4. Time attributes: In general, I like your computed
> >> columns
> >>>>>>>>>> approach
> >>>>>>>>>>>>>>> because it makes defining a rowtime attributes transparent
> >>> and
> >>>>>>>>>>> simple.
> >>>>>>>>>>>>>>> However, there are downsides that we should discuss.
> >>>>>>>>>>>>>>> 4a. Jarks current design means that timestamps are in the
> >>>>>> schema
> >>>>>>>>>>> twice.
> >>>>>>>>>>>>>>> The design that is mentioned in [1] makes this more
> >> flexible
> >>> as
> >>>>>>> it
> >>>>>>>>>>>>>>> either allows to replace an existing column or add a
> >> computed
> >>>>>>>>>> column.
> >>>>>>>>>>>>>>> 4b. We need to consider the zoo of storage systems that is
> >>> out
> >>>>>>>>>> there
> >>>>>>>>>>>>>>> right now. Take Kafka as an example, how can we write out a
> >>>>>>>>>> timestamp
> >>>>>>>>>>>>>>> into the message header? We need to think of a reverse
> >>>>>> operation
> >>>>>>>>>> to a
> >>>>>>>>>>>>>>> computed column.
> >>>>>>>>>>>>>>> 4c. Does defining a watermark really fit into the schema
> >> part
> >>>>>> of
> >>>>>>> a
> >>>>>>>>>>>>>>> table? Shouldn't we separate all time attribute concerns
> >>> into a
> >>>>>>>>>>> special
> >>>>>>>>>>>>>>> clause next to the regular schema, similar how PARTITIONED
> >> BY
> >>>>>>> does
> >>>>>>>>>> it
> >>>>>>>>>>>> in
> >>>>>>>>>>>>>>> Hive?
> >>>>>>>>>>>>>>> 4d. How can people come up with a custom watermark
> >> strategy?
> >>> I
> >>>>>>>>>> guess
> >>>>>>>>>>>>>>> this can not be implemented in a scalar function and would
> >>>>>>> require
> >>>>>>>>>>> some
> >>>>>>>>>>>>>>> new type of UDF?
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> 6. Partitioning and keys: Another question that the DDL
> >>> design
> >>>>>>>>>> should
> >>>>>>>>>>>>>>> answer is how do we express primary keys (for upserts),
> >>>>>>>>>> partitioning
> >>>>>>>>>>>>>>> keys (for Hive, Kafka message keys). All part of the table
> >>>>>>> schema?
> >>>>>>>>>>>>>>> 5. Schema declaration: I find it very annoying that we want
> >>> to
> >>>>>>>>>> force
> >>>>>>>>>>>>>>> people to declare all columns and types again even though
> >>> this
> >>>>>> is
> >>>>>>>>>>>>>>> usually already defined in some company-wide format. I know
> >>>>>> that
> >>>>>>>>>>>> catalog
> >>>>>>>>>>>>>>> support will greatly improve this. But if no catalog is
> >> used,
> >>>>>>>>>> people
> >>>>>>>>>>>>>>> need to manually define a schema with 50+ fields in a Flink
> >>>>>> DDL.
> >>>>>>>>>>> What I
> >>>>>>>>>>>>>>> actually promoted having two ways of reading data:
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> 1. Either the format derives its schema from the table
> >>> schema.
> >>>>>>>>>>>>>>> CREATE TABLE (col INT) WITH (format.type = avro)
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> 2. Or the table schema can be omitted and the format schema
> >>>>>>> defines
> >>>>>>>>>>> the
> >>>>>>>>>>>>>>> table schema (+ time attributes).
> >>>>>>>>>>>>>>> CREATE TABLE WITH (format.type = avro, format.schema-file =
> >>>>>>>>>>>>>>> "/my/avrofile.avsc")
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> Please let me know what you think about each item. I will
> >> try
> >>>>>> to
> >>>>>>>>>>>>>>> incorporate your feedback in [1] this week.
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>>> Timo
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>
> >>
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit#heading=h.41fd6rs7b3cf
> >>>>>>>>>>>>>>> Am 05.12.18 um 13:01 schrieb Jark Wu:
> >>>>>>>>>>>>>>>> Hi Shuyi,
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> It's exciting to see we can make such a great progress
> >> here.
> >>>>>>>>>>>>>>>> Regarding to the watermark:
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> Watermarks can be defined on any columns (including
> >>>>>>>>>> computed-column)
> >>>>>>>>>>>> in
> >>>>>>>>>>>>>>>> table schema.
> >>>>>>>>>>>>>>>> The computed column can be computed from existing columns
> >>>>>> using
> >>>>>>>>>>>> builtin
> >>>>>>>>>>>>>>>> functions and *UserDefinedFunctions* (ScalarFunction).
> >>>>>>>>>>>>>>>> So IMO, it can work out for almost all the scenarios not
> >>> only
> >>>>>>>>>> common
> >>>>>>>>>>>>>>>> scenarios.
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> I don't think using a `TimestampExtractor` to support
> >> custom
> >>>>>>>>>>> timestamp
> >>>>>>>>>>>>>>>> extractor in SQL is a good idea. Because
> >>> `TimestampExtractor`
> >>>>>>>>>>>>>>>> is not a SQL standard function. If we support
> >>>>>>> `TimestampExtractor`
> >>>>>>>>>>> in
> >>>>>>>>>>>>>>> SQL,
> >>>>>>>>>>>>>>>> do we need to support CREATE FUNCTION for
> >>>>>> `TimestampExtractor`?
> >>>>>>>>>>>>>>>> I think `ScalarFunction` can do the same thing with
> >>>>>>>>>>>>>> `TimestampExtractor`
> >>>>>>>>>>>>>>>> but more powerful and standard.
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> The core idea of the watermark definition syntax is that
> >> the
> >>>>>>>>>> schema
> >>>>>>>>>>>>>> part
> >>>>>>>>>>>>>>>> defines all the columns of the table, it is exactly what
> >> the
> >>>>>>> query
> >>>>>>>>>>>>>> sees.
> >>>>>>>>>>>>>>>> The watermark part is something like a primary key
> >>> definition
> >>>>>> or
> >>>>>>>>>>>>>>> constraint
> >>>>>>>>>>>>>>>> on SQL Table, it has no side effect on the schema, only
> >>>>>> defines
> >>>>>>>>>> what
> >>>>>>>>>>>>>>>> watermark strategy is and makes which field as the rowtime
> >>>>>>>>>> attribute
> >>>>>>>>>>>>>>> field.
> >>>>>>>>>>>>>>>> If the rowtime field is not in the existing fields, we can
> >>> use
> >>>>>>>>>>>> computed
> >>>>>>>>>>>>>>>> column
> >>>>>>>>>>>>>>>> to generate it from other existing fields. The Descriptor
> >>>>>>> Pattern
> >>>>>>>>>>> API
> >>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>> is very useful when writing a Table API job, but is not
> >>>>>>>>>>> contradictory
> >>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>> Watermark DDL from my perspective.
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> [1]:
> >>>>>>>>>>>>>>>>
> >>
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> >>>>>>>>>>>>>>>> .
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> Best,
> >>>>>>>>>>>>>>>> Jark
> >>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>> On Wed, 5 Dec 2018 at 17:58, Shuyi Chen <
> >> [hidden email]
> >>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>> Hi Jark and Shaoxuan,
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> Thanks a lot for the summary. I think we are making great
> >>>>>>>>>> progress
> >>>>>>>>>>>>>> here.
> >>>>>>>>>>>>>>>>> Below are my thoughts.
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> *(1) watermark definition
> >>>>>>>>>>>>>>>>> IMO, it's better to keep it consistent with the rowtime
> >>>>>>>>>> extractors
> >>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>> watermark strategies defined in
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>
> >>
> https://ci.apache.org/projects/flink/flink-docs-stable/dev/table/connect.html#rowtime-attributes
> >>>>>>>>>>>>>>>>> .
> >>>>>>>>>>>>>>>>> Using built-in functions seems to be too much for most of
> >>> the
> >>>>>>>>>>> common
> >>>>>>>>>>>>>>>>> scenarios.
> >>>>>>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> >>>>>>>>>>>>>>>>> Actually, I think we can put the source/sink type info
> >> into
> >>>>>> the
> >>>>>>>>>>> table
> >>>>>>>>>>>>>>>>> properties, so we can use CREATE TABLE.
> >>>>>>>>>>>>>>>>> (3) View DDL with properties
> >>>>>>>>>>>>>>>>> We can remove the view properties section now for the MVP
> >>> and
> >>>>>>> add
> >>>>>>>>>>> it
> >>>>>>>>>>>>>>> back
> >>>>>>>>>>>>>>>>> later if needed.
> >>>>>>>>>>>>>>>>> (4) Type Definition
> >>>>>>>>>>>>>>>>> I agree we can put the type length or precision into
> >> future
> >>>>>>>>>>> versions.
> >>>>>>>>>>>>>> As
> >>>>>>>>>>>>>>>>> for the grammar difference, currently, I am using the
> >>> grammar
> >>>>>>> in
> >>>>>>>>>>>>>> Calcite
> >>>>>>>>>>>>>>>>> type DDL, but since we'll extend the parser in Flink, so
> >> we
> >>>>>> can
> >>>>>>>>>>>>>>> definitely
> >>>>>>>>>>>>>>>>> change if needed.
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> Shuyi
> >>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>> On Tue, Dec 4, 2018 at 10:48 PM Jark Wu <
> >> [hidden email]>
> >>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>> Hi Shaoxuan,
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> Thanks for pointing that out. Yes, the source/sink tag
> >> on
> >>>>>>> create
> >>>>>>>>>>>>>> table
> >>>>>>>>>>>>>>> is
> >>>>>>>>>>>>>>>>>> the another major difference.
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> Summarize the main differences again:
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> *(1) watermark definition
> >>>>>>>>>>>>>>>>>> *(2) CREATE SOURCE/SINK TABLE or CREATE TABLE
> >>>>>>>>>>>>>>>>>> (3) View DDL with properties
> >>>>>>>>>>>>>>>>>> (4) Type Definition
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> Best,
> >>>>>>>>>>>>>>>>>> Jark
> >>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>> On Wed, 5 Dec 2018 at 14:08, Shaoxuan Wang <
> >>>>>>> [hidden email]
> >>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>> Hi Jark,
> >>>>>>>>>>>>>>>>>>> Thanks for the summary. Your plan for the 1st round
> >>>>>>>>>>> implementation
> >>>>>>>>>>>>>> of
> >>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>> looks good to me.
> >>>>>>>>>>>>>>>>>>> Have we reached the agreement on simplifying/unifying
> >>>>>> "create
> >>>>>>>>>>>>>>>>>> [source/sink]
> >>>>>>>>>>>>>>>>>>> table" to "create table"? "Watermark definition" and
> >>>>>> "create
> >>>>>>>>>>> table"
> >>>>>>>>>>>>>>> are
> >>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>> major obstacles on the way to merge two design
> >> proposals
> >>>>>>> FMPOV.
> >>>>>>>>>>>>>>> @Shuyi,
> >>>>>>>>>>>>>>>>>> It
> >>>>>>>>>>>>>>>>>>> would be great if you can spend time and respond to
> >> these
> >>>>>> two
> >>>>>>>>>>> parts
> >>>>>>>>>>>>>>>>>> first.
> >>>>>>>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>>>>>>> Shaoxuan
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>> On Wed, Dec 5, 2018 at 12:20 PM Jark Wu <
> >>> [hidden email]>
> >>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> It seems that you have reviewed the DDL doc [1] that
> >> Lin
> >>>>>>> and I
> >>>>>>>>>>>>>>>>> drafted.
> >>>>>>>>>>>>>>>>>>>> This doc covers all the features running in Alibaba.
> >>>>>>>>>>>>>>>>>>>> But some of features might be not needed in the first
> >>>>>>> version
> >>>>>>>>>> of
> >>>>>>>>>>>>>>>>> Flink
> >>>>>>>>>>>>>>>>>>> SQL
> >>>>>>>>>>>>>>>>>>>> DDL.
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> So my suggestion would be to focus on the MVP DDLs and
> >>>>>> reach
> >>>>>>>>>>>>>>>>> agreement
> >>>>>>>>>>>>>>>>>>> ASAP
> >>>>>>>>>>>>>>>>>>>> based on the DDL draft [1] and the DDL design [2]
> >> Shuyi
> >>>>>>>>>>> proposed.
> >>>>>>>>>>>>>>>>>>>> And we can discuss on the main differences one by one.
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> The following is the MVP DDLs should be included in
> >> the
> >>>>>>> first
> >>>>>>>>>>>>>> version
> >>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>> my
> >>>>>>>>>>>>>>>>>>>> opinion (feedbacks are welcome):
> >>>>>>>>>>>>>>>>>>>> (1) Table DDL:
> >>>>>>>>>>>>>>>>>>>>          (1.1) Type definition
> >>>>>>>>>>>>>>>>>>>>          (1.2) computed column definition
> >>>>>>>>>>>>>>>>>>>>          (1.3) watermark definition
> >>>>>>>>>>>>>>>>>>>>          (1.4) with properties
> >>>>>>>>>>>>>>>>>>>>          (1.5) table constraint (primary key/unique)
> >>>>>>>>>>>>>>>>>>>>          (1.6) column nullability (nice to have)
> >>>>>>>>>>>>>>>>>>>> (2) View DDL
> >>>>>>>>>>>>>>>>>>>> (3) Function DDL
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> The main differences from two DDL docs (sth maybe
> >>> missed,
> >>>>>>>>>>> welcome
> >>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>> point
> >>>>>>>>>>>>>>>>>>>> out):
> >>>>>>>>>>>>>>>>>>>> *(1.3) watermark*: this is the main and the most
> >>> important
> >>>>>>>>>>>>>>>>> difference,
> >>>>>>>>>>>>>>>>>> it
> >>>>>>>>>>>>>>>>>>>> would be great if @Timo Walther <[hidden email]>
> >>>>>>> @Fabian
> >>>>>>>>>>>>>> Hueske
> >>>>>>>>>>>>>>>>>>>> <[hidden email]>  give some feedbacks.
> >>>>>>>>>>>>>>>>>>>>       (1.1) Type definition:
> >>>>>>>>>>>>>>>>>>>>            (a) Should VARCHAR carry a length, e.g.
> >>>>>>> VARCHAR(128)
> >>>>>>>> ?
> >>>>>>>>>>>>>>>>>>>>                 In most cases, the varchar length is
> >> not
> >>>>>> used
> >>>>>>>>>>> because
> >>>>>>>>>>>>>>> they
> >>>>>>>>>>>>>>>>>> are
> >>>>>>>>>>>>>>>>>>>> stored as String in Flink. But it can be used to
> >>> optimize
> >>>>>> in
> >>>>>>>>>> the
> >>>>>>>>>>>>>>>>> future
> >>>>>>>>>>>>>>>>>>> if
> >>>>>>>>>>>>>>>>>>>> we know the column is a fixed length VARCHAR.
> >>>>>>>>>>>>>>>>>>>>                 So IMO, we can support VARCHAR with
> >>> length
> >>>>>> in
> >>>>>>>> the
> >>>>>>>>>>>>>> future,
> >>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>> just VARCHAR in this version.
> >>>>>>>>>>>>>>>>>>>>            (b) Should DECIMAL support custom scale and
> >>>>>>>> precision,
> >>>>>>>>>>>> e.g.
> >>>>>>>>>>>>>>>>>>>> DECIMAL(12, 5)?
> >>>>>>>>>>>>>>>>>>>>                 If we clearly know the scale and
> >>> precision
> >>>>>> of
> >>>>>>>> the
> >>>>>>>>>>>>>>> Decimal,
> >>>>>>>>>>>>>>>>>> we
> >>>>>>>>>>>>>>>>>>>> can have some optimization on
> >>>>>> serialization/deserialization.
> >>>>>>>>>>> IMO,
> >>>>>>>>>>>>>> we
> >>>>>>>>>>>>>>>>>> can
> >>>>>>>>>>>>>>>>>>>> support just support DECIMAL in this version,
> >>>>>>>>>>>>>>>>>>>>                 which means DECIMAL(38, 18) as
> default.
> >>> And
> >>>>>>>>>> support
> >>>>>>>>>>>>>>> custom
> >>>>>>>>>>>>>>>>>>> scale
> >>>>>>>>>>>>>>>>>>>> and precision in the future.
> >>>>>>>>>>>>>>>>>>>>       (2) View DDL: Do we need WITH properties in View
> >>> DDL
> >>>>>>>>>>> (proposed
> >>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>> doc[2])?
> >>>>>>>>>>>>>>>>>>>> What are the properties on the view used for?
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> The features could be supported and discussed in the
> >>>>>> future:
> >>>>>>>>>>>>>>>>>>>> (1) period definition on table
> >>>>>>>>>>>>>>>>>>>> (2) Type DDL
> >>>>>>>>>>>>>>>>>>>> (3) Index DDL
> >>>>>>>>>>>>>>>>>>>> (4) Library DDL
> >>>>>>>>>>>>>>>>>>>> (5) Drop statement
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> [1] Flink DDL draft by Lin and Jark:
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>
> >>
> https://docs.google.com/document/d/1o16jC-AxnZoxMfHQptkKQkSC6ZDDBRhKg6gm8VGnY-k/edit#
> >>>>>>>>>>>>>>>>>>>> [2] Flink SQL DDL design by Shuyi:
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>
> >>
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit#
> >>>>>>>>>>>>>>>>>>>> Cheers,
> >>>>>>>>>>>>>>>>>>>> Jark
> >>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>> On Thu, 29 Nov 2018 at 16:13, Shaoxuan Wang <
> >>>>>>>>>>> [hidden email]>
> >>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>> Sure Shuyu,
> >>>>>>>>>>>>>>>>>>>>> What I hope is that we can reach an agreement on DDL
> >>>>>> gramma
> >>>>>>>>>> as
> >>>>>>>>>>>>>> soon
> >>>>>>>>>>>>>>>>>> as
> >>>>>>>>>>>>>>>>>>>>> possible. There are a few differences between your
> >>>>>> proposal
> >>>>>>>>>> and
> >>>>>>>>>>>>>>>>> ours.
> >>>>>>>>>>>>>>>>>>>> Once
> >>>>>>>>>>>>>>>>>>>>> Lin and Jark propose our design, we can quickly
> >> discuss
> >>>>>> on
> >>>>>>>>>> the
> >>>>>>>>>>>>>>>>> those
> >>>>>>>>>>>>>>>>>>>>> differences, and see how far away towards a unified
> >>>>>> design.
> >>>>>>>>>>>>>>>>>>>>> WRT the external catalog, I think it is an orthogonal
> >>>>>>> topic,
> >>>>>>>>>> we
> >>>>>>>>>>>>>> can
> >>>>>>>>>>>>>>>>>>>> design
> >>>>>>>>>>>>>>>>>>>>> it in parallel. I believe @Xuefu, @Bowen are already
> >>>>>>> working
> >>>>>>>>>>> on.
> >>>>>>>>>>>>>> We
> >>>>>>>>>>>>>>>>>>>>> should/will definitely involve them to review the
> >> final
> >>>>>>>>>> design
> >>>>>>>>>>> of
> >>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>> implementation. I would suggest that we should give
> >> it
> >>> a
> >>>>>>>>>> higher
> >>>>>>>>>>>>>>>>>>> priority
> >>>>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>>> the DDL implementation, as it is a crucial component
> >>> for
> >>>>>>> the
> >>>>>>>>>>> user
> >>>>>>>>>>>>>>>>>>>>> experience of SQL_CLI.
> >>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>>>>>>>>> Shaoxuan
> >>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>> On Thu, Nov 29, 2018 at 6:56 AM Shuyi Chen <
> >>>>>>>>>> [hidden email]
> >>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Shaoxuan, Jack and Lin. We should
> >>>>>> definitely
> >>>>>>>>>>>>>>>>>>> collaborate
> >>>>>>>>>>>>>>>>>>>>>> here, we have also our own DDL implementation
> >> running
> >>> in
> >>>>>>>>>>>>>>>>> production
> >>>>>>>>>>>>>>>>>>> for
> >>>>>>>>>>>>>>>>>>>>>> almost 2 years at Uber. With the joint experience
> >> from
> >>>>>>> both
> >>>>>>>>>>>>>>>>>>> companies,
> >>>>>>>>>>>>>>>>>>>> we
> >>>>>>>>>>>>>>>>>>>>>> can definitely make the Flink SQL DDL better.
> >>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>> As @shaoxuan suggest, Jark can come up with a doc
> >> that
> >>>>>>> talks
> >>>>>>>>>>>>>>>>> about
> >>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>> current DDL design in Alibaba, and we can discuss
> >> and
> >>>>>>> merge
> >>>>>>>>>>> them
> >>>>>>>>>>>>>>>>>> into
> >>>>>>>>>>>>>>>>>>>>> one,
> >>>>>>>>>>>>>>>>>>>>>> make it as a FLIP, and plan the tasks for
> >>>>>> implementation.
> >>>>>>>>>>> Also,
> >>>>>>>>>>>>>>>>> we
> >>>>>>>>>>>>>>>>>>>> should
> >>>>>>>>>>>>>>>>>>>>>> take into account the new external catalog effort in
> >>> the
> >>>>>>>>>>> design.
> >>>>>>>>>>>>>>>>>> What
> >>>>>>>>>>>>>>>>>>>> do
> >>>>>>>>>>>>>>>>>>>>>> you guys think?
> >>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>> Shuyi
> >>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 6:45 AM Jark Wu <
> >>>>>> [hidden email]
> >>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>>> Hi Shaoxuan,
> >>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>> I think summarizing it into a google doc is a good
> >>>>>> idea.
> >>>>>>> We
> >>>>>>>>>>>>>>>>> will
> >>>>>>>>>>>>>>>>>>>>> prepare
> >>>>>>>>>>>>>>>>>>>>>> it
> >>>>>>>>>>>>>>>>>>>>>>> in the next few days.
> >>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>> Thanks,
> >>>>>>>>>>>>>>>>>>>>>>> Jark
> >>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>> Shaoxuan Wang <[hidden email]> 于2018年11月28日周三
> >>>>>>>>>> 下午9:17写道：
> >>>>>>>>>>>>>>>>>>>>>>>> Hi Lin and Jark,
> >>>>>>>>>>>>>>>>>>>>>>>> Thanks for sharing those details. Can you please
> >>>>>>> consider
> >>>>>>>>>>>>>>>>>>>> summarizing
> >>>>>>>>>>>>>>>>>>>>>>> your
> >>>>>>>>>>>>>>>>>>>>>>>> DDL design into a google doc.
> >>>>>>>>>>>>>>>>>>>>>>>> We can still continue the discussions on Shuyi's
> >>>>>>> proposal.
> >>>>>>>>>>>>>>>>> But
> >>>>>>>>>>>>>>>>>>>>> having a
> >>>>>>>>>>>>>>>>>>>>>>>> separate google doc will be easy for the DEV to
> >>>>>>>>>>>>>>>>>>>>>>> understand/comment/discuss
> >>>>>>>>>>>>>>>>>>>>>>>> on your proposed DDL implementation.
> >>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>>>>>>>>>>>> Shaoxuan
> >>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>> On Wed, Nov 28, 2018 at 7:39 PM Jark Wu <
> >>>>>>> [hidden email]
> >>>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>> Thanks for bringing up this discussion and the
> >>>>>> awesome
> >>>>>>>>>>>>>>>>> work!
> >>>>>>>>>>>>>>>>>> I
> >>>>>>>>>>>>>>>>>>>> have
> >>>>>>>>>>>>>>>>>>>>>>> left
> >>>>>>>>>>>>>>>>>>>>>>>>> some comments in the doc.
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>> I want to share something more about the
> >> watermark
> >>>>>>>>>>>>>>>>> definition
> >>>>>>>>>>>>>>>>>>>>> learned
> >>>>>>>>>>>>>>>>>>>>>>>> from
> >>>>>>>>>>>>>>>>>>>>>>>>> Alibaba.
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>         1.
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>         Table should be able to accept multiple
> >>>>>> watermark
> >>>>>>>>>>>>>>>>>>> definition.
> >>>>>>>>>>>>>>>>>>>>>>>>>         Because a table may have more than one
> >>> rowtime
> >>>>>>>>>> field.
> >>>>>>>>>>>>>>>>> For
> >>>>>>>>>>>>>>>>>>>>> example,
> >>>>>>>>>>>>>>>>>>>>>>> one
> >>>>>>>>>>>>>>>>>>>>>>>>>         rowtime field is from existing field but
> >>>>>> missing
> >>>>>>> in
> >>>>>>>>>>> some
> >>>>>>>>>>>>>>>>>>>>> records,
> >>>>>>>>>>>>>>>>>>>>>>>>> another
> >>>>>>>>>>>>>>>>>>>>>>>>>         is the ingestion timestamp in Kafka but
> >> not
> >>>>>> very
> >>>>>>>>>>>>>>>>> accurate.
> >>>>>>>>>>>>>>>>>>> In
> >>>>>>>>>>>>>>>>>>>>> this
> >>>>>>>>>>>>>>>>>>>>>>>> case,
> >>>>>>>>>>>>>>>>>>>>>>>>>         user may define two rowtime fields with
> >>>>>>> watermarks
> >>>>>>>>>> in
> >>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>> Table
> >>>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>> choose
> >>>>>>>>>>>>>>>>>>>>>>>>>         one in different situation.
> >>>>>>>>>>>>>>>>>>>>>>>>>         2.
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>         Watermark stragety always work with
> >> rowtime
> >>>>>> field
> >>>>>>>>>>>>>>>>>> together.
> >>>>>>>>>>>>>>>>>>>>>>>>> Based on the two points metioned above, I think
> >> we
> >>>>>>> should
> >>>>>>>>>>>>>>>>>>> combine
> >>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>> watermark strategy and rowtime field selection
> >>> (i.e.
> >>>>>>>>>> which
> >>>>>>>>>>>>>>>>>>>> existing
> >>>>>>>>>>>>>>>>>>>>>>> field
> >>>>>>>>>>>>>>>>>>>>>>>>> used to generate watermark) in one clause, so
> >> that
> >>> we
> >>>>>>> can
> >>>>>>>>>>>>>>>>>>> define
> >>>>>>>>>>>>>>>>>>>>>>> multiple
> >>>>>>>>>>>>>>>>>>>>>>>>> watermarks in one Table.
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>> Here I will share the watermark syntax used in
> >>>>>> Alibaba
> >>>>>>>>>>>>>>>>>> (simply
> >>>>>>>>>>>>>>>>>>>>>>> modified):
> >>>>>>>>>>>>>>>>>>>>>>>>> watermarkDefinition:
> >>>>>>>>>>>>>>>>>>>>>>>>> WATERMARK [watermarkName] FOR <rowtime_field> AS
> >>>>>>>>>>>>>>>>> wm_strategy
> >>>>>>>>>>>>>>>>>>>>>>>>> wm_strategy:
> >>>>>>>>>>>>>>>>>>>>>>>>>        BOUNDED WITH OFFSET 'string' timeUnit
> >>>>>>>>>>>>>>>>>>>>>>>>> |
> >>>>>>>>>>>>>>>>>>>>>>>>>        ASCENDING
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>> The “WATERMARK” keyword starts a watermark
> >>>>>> definition.
> >>>>>>>>>> The
> >>>>>>>>>>>>>>>>>>> “FOR”
> >>>>>>>>>>>>>>>>>>>>>>> keyword
> >>>>>>>>>>>>>>>>>>>>>>>>> defines which existing field used to generate
> >>>>>>> watermark,
> >>>>>>>>>>>>>>>>> this
> >>>>>>>>>>>>>>>>>>>> field
> >>>>>>>>>>>>>>>>>>>>>>>> should
> >>>>>>>>>>>>>>>>>>>>>>>>> already exist in the schema (we can use
> >>>>>> computed-column
> >>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>> derive
> >>>>>>>>>>>>>>>>>>>>>> from
> >>>>>>>>>>>>>>>>>>>>>>>>> other fields). The “AS” keyword defines watermark
> >>>>>>>>>> strategy,
> >>>>>>>>>>>>>>>>>>> such
> >>>>>>>>>>>>>>>>>>>> as
> >>>>>>>>>>>>>>>>>>>>>>>> BOUNDED
> >>>>>>>>>>>>>>>>>>>>>>>>> WITH OFFSET (covers almost all the requirements)
> >>> and
> >>>>>>>>>>>>>>>>>> ASCENDING.
> >>>>>>>>>>>>>>>>>>>>>>>>> When the expected rowtime field does not exist in
> >>> the
> >>>>>>>>>>>>>>>>> schema,
> >>>>>>>>>>>>>>>>>>> we
> >>>>>>>>>>>>>>>>>>>>> can
> >>>>>>>>>>>>>>>>>>>>>>> use
> >>>>>>>>>>>>>>>>>>>>>>>>> computed-column syntax to derive it from other
> >>>>>> existing
> >>>>>>>>>>>>>>>>>> fields
> >>>>>>>>>>>>>>>>>>>>> using
> >>>>>>>>>>>>>>>>>>>>>>>>> built-in functions or user defined functions. So
> >>> the
> >>>>>>>>>>>>>>>>>>>>>> rowtime/watermark
> >>>>>>>>>>>>>>>>>>>>>>>>> definition doesn’t need to care about
> >>> “field-change”
> >>>>>>>>>>>>>>>>> strategy
> >>>>>>>>>>>>>>>>>>>>>>>>> (replace/add/from-field). And the proctime field
> >>>>>>>>>> definition
> >>>>>>>>>>>>>>>>>> can
> >>>>>>>>>>>>>>>>>>>>> also
> >>>>>>>>>>>>>>>>>>>>>> be
> >>>>>>>>>>>>>>>>>>>>>>>>> defined using computed-column. Such as pt as
> >>>>>> PROCTIME()
> >>>>>>>>>>>>>>>>> which
> >>>>>>>>>>>>>>>>>>>>>> defines a
> >>>>>>>>>>>>>>>>>>>>>>>>> proctime field named “pt” in the schema.
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>> Looking forward to working with you guys!
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>> Best,
> >>>>>>>>>>>>>>>>>>>>>>>>> Jark Wu
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>> Lin Li <[hidden email]> 于2018年11月28日周三
> >>>>>>> 下午6:33写道：
> >>>>>>>>>>>>>>>>>>>>>>>>>> @Shuyi
> >>>>>>>>>>>>>>>>>>>>>>>>>> Thanks for the proposal!  We have a simple DDL
> >>>>>>>>>>>>>>>>>> implementation
> >>>>>>>>>>>>>>>>>>>>>>> (extends
> >>>>>>>>>>>>>>>>>>>>>>>>>> Calcite's parser) which been running for almost
> >>> two
> >>>>>>>>>> years
> >>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>>>>> production
> >>>>>>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>>> works well.
> >>>>>>>>>>>>>>>>>>>>>>>>>> I think the most valued things we'd learned is
> >>>>>> keeping
> >>>>>>>>>>>>>>>>>>>> simplicity
> >>>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>>> standard compliance.
> >>>>>>>>>>>>>>>>>>>>>>>>>> Here's the approximate grammar, FYI
> >>>>>>>>>>>>>>>>>>>>>>>>>> CREATE TABLE
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> CREATE TABLE tableName(
> >>>>>>>>>>>>>>>>>>>>>>>>>>              columnDefinition [,
> >> columnDefinition]*
> >>>>>>>>>>>>>>>>>>>>>>>>>>              [ computedColumnDefinition [,
> >>>>>>>>>>>>>>>>>>>> computedColumnDefinition]*
> >>>>>>>>>>>>>>>>>>>>> ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>              [ tableConstraint [,
> >>> tableConstraint]* ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>              [ tableIndex [, tableIndex]* ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>          [ PERIOD FOR SYSTEM_TIME ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>              [ WATERMARK watermarkName FOR
> >>>>>> rowTimeColumn
> >>>>>>>> AS
> >>>>>>>>>>>>>>>>>>>>>>>>>> withOffset(rowTimeColumn, offset) ]     ) [
> >> WITH (
> >>>>>>>>>>>>>>>>>>> tableOption
> >>>>>>>>>>>>>>>>>>>> [
> >>>>>>>>>>>>>>>>>>>>> ,
> >>>>>>>>>>>>>>>>>>>>>>>>>> tableOption]* ) ] [ ; ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> columnDefinition ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              columnName dataType [ NOT NULL ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> dataType  ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              {
> >>>>>>>>>>>>>>>>>>>>>>>>>>                [ VARCHAR ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ BOOLEAN ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ TINYINT ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ SMALLINT ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ INT ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ BIGINT ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ FLOAT ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ DECIMAL ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ DOUBLE ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ DATE ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ TIME ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ TIMESTAMP ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>                | [ VARBINARY ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>              }
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> computedColumnDefinition ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              columnName AS
> >> computedColumnExpression
> >>>>>>>>>>>>>>>>>>>>>>>>>> tableConstraint ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>          { PRIMARY KEY | UNIQUE }
> >>>>>>>>>>>>>>>>>>>>>>>>>>              (columnName [, columnName]* )
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> tableIndex ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              [ UNIQUE ] INDEX indexName
> >>>>>>>>>>>>>>>>>>>>>>>>>>               (columnName [, columnName]* )
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> rowTimeColumn ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              columnName
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> tableOption ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              property=value
> >>>>>>>>>>>>>>>>>>>>>>>>>>              offset ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              positive integer (unit: ms)
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> CREATE VIEW
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> CREATE VIEW viewName
> >>>>>>>>>>>>>>>>>>>>>>>>>>        [
> >>>>>>>>>>>>>>>>>>>>>>>>>>              ( columnName [, columnName]* )
> >>>>>>>>>>>>>>>>>>>>>>>>>>        ]
> >>>>>>>>>>>>>>>>>>>>>>>>>>              AS queryStatement;
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> CREATE FUNCTION
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>       CREATE FUNCTION functionName
> >>>>>>>>>>>>>>>>>>>>>>>>>>        AS 'className';
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>       className ::=
> >>>>>>>>>>>>>>>>>>>>>>>>>>              fully qualified name
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi Chen <[hidden email]> 于2018年11月28日周三
> >>>>>>>>>> 上午3:28写道：
> >>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Timo and Xuefu. Yes, I think we
> >> can
> >>>>>>>>>>>>>>>>>> finalize
> >>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>> design
> >>>>>>>>>>>>>>>>>>>>>>>>> doc
> >>>>>>>>>>>>>>>>>>>>>>>>>>> first and start implementation w/o the unified
> >>>>>>>>>>>>>>>>> connector
> >>>>>>>>>>>>>>>>>>> API
> >>>>>>>>>>>>>>>>>>>>>> ready
> >>>>>>>>>>>>>>>>>>>>>>> by
> >>>>>>>>>>>>>>>>>>>>>>>>>>> skipping some featue.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu, I like the idea of making Flink specific
> >>>>>>>>>>>>>>>>>> properties
> >>>>>>>>>>>>>>>>>>>> into
> >>>>>>>>>>>>>>>>>>>>>>>> generic
> >>>>>>>>>>>>>>>>>>>>>>>>>>> key-value pairs, so that it will make
> >> integration
> >>>>>>> with
> >>>>>>>>>>>>>>>>>> Hive
> >>>>>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>>> (or
> >>>>>>>>>>>>>>>>>>>>>>>>>> others,
> >>>>>>>>>>>>>>>>>>>>>>>>>>> e.g. Beam DDL) easier.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>> I'll run a final pass over the design doc and
> >>>>>>> finalize
> >>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>> design
> >>>>>>>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>> next few days. And we can start creating tasks
> >>> and
> >>>>>>>>>>>>>>>>>>>> collaborate
> >>>>>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>> implementation. Thanks a lot for all the
> >> comments
> >>>>>> and
> >>>>>>>>>>>>>>>>>>> inputs.
> >>>>>>>>>>>>>>>>>>>>>>>>>>> Cheers!
> >>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi
> >>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>> On Tue, Nov 27, 2018 at 7:02 AM Zhang, Xuefu <
> >>>>>>>>>>>>>>>>>>>>>>>> [hidden email]>
> >>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Yeah! I agree with Timo that DDL can actually
> >>>>>>> proceed
> >>>>>>>>>>>>>>>>>> w/o
> >>>>>>>>>>>>>>>>>>>>> being
> >>>>>>>>>>>>>>>>>>>>>>>>> blocked
> >>>>>>>>>>>>>>>>>>>>>>>>>>> by
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> connector API. We can leave the unknown out
> >>> while
> >>>>>>>>>>>>>>>>>>> defining
> >>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>> basic
> >>>>>>>>>>>>>>>>>>>>>>>>>>> syntax.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> @Shuyi
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> As commented in the doc, I think we can
> >> probably
> >>>>>>>>>>>>>>>>> stick
> >>>>>>>>>>>>>>>>>>> with
> >>>>>>>>>>>>>>>>>>>>>>> simple
> >>>>>>>>>>>>>>>>>>>>>>>>>> syntax
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> with general properties, without extending the
> >>>>>>> syntax
> >>>>>>>>>>>>>>>>>> too
> >>>>>>>>>>>>>>>>>>>>> much
> >>>>>>>>>>>>>>>>>>>>>>> that
> >>>>>>>>>>>>>>>>>>>>>>>>> it
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> mimics the descriptor API.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Part of our effort on Flink-Hive integration
> >> is
> >>>>>> also
> >>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>> make
> >>>>>>>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>>>>>> syntax
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> compatible with Hive's. The one in the current
> >>>>>>>>>>>>>>>>> proposal
> >>>>>>>>>>>>>>>>>>>> seems
> >>>>>>>>>>>>>>>>>>>>>>>> making
> >>>>>>>>>>>>>>>>>>>>>>>>>> our
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> effort more challenging.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> We can help and collaborate. At this moment, I
> >>>>>> think
> >>>>>>>>>>>>>>>>> we
> >>>>>>>>>>>>>>>>>>> can
> >>>>>>>>>>>>>>>>>>>>>>>> finalize
> >>>>>>>>>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> the proposal and then we can divide the tasks
> >>> for
> >>>>>>>>>>>>>>>>>> better
> >>>>>>>>>>>>>>>>>>>>>>>>> collaboration.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Please let me know if there are  any questions
> >>> or
> >>>>>>>>>>>>>>>>>>>>> suggestions.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >> ------------------------------------------------------------------
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Sender:Timo Walther <[hidden email]>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Sent at:2018 Nov 27 (Tue) 16:21
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Recipient:dev <[hidden email]>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Subject:Re: [DISCUSS] Flink SQL DDL Design
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks for offering your help here, Xuefu. It
> >>>>>> would
> >>>>>>>>>>>>>>>>> be
> >>>>>>>>>>>>>>>>>>>> great
> >>>>>>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>>>>>> move
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> these efforts forward. I agree that the DDL is
> >>>>>>>>>>>>>>>>> somehow
> >>>>>>>>>>>>>>>>>>>>> releated
> >>>>>>>>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> unified connector API design but we can also
> >>> start
> >>>>>>>>>>>>>>>>> with
> >>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>> basic
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> functionality now and evolve the DDL during
> >> this
> >>>>>>>>>>>>>>>>>> release
> >>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>> next
> >>>>>>>>>>>>>>>>>>>>>>>>>>> releases.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> For example, we could identify the MVP DDL
> >>> syntax
> >>>>>>>>>>>>>>>>> that
> >>>>>>>>>>>>>>>>>>>> skips
> >>>>>>>>>>>>>>>>>>>>>>>> defining
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> key constraints and maybe even time
> >> attributes.
> >>>>>> This
> >>>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>> could
> >>>>>>>>>>>>>>>>>>>>>> be
> >>>>>>>>>>>>>>>>>>>>>>>>> used
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> for batch usecases, ETL, and materializing SQL
> >>>>>>>>>>>>>>>>> queries
> >>>>>>>>>>>>>>>>>>> (no
> >>>>>>>>>>>>>>>>>>>>> time
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> operations like windows).
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> The unified connector API is high on our
> >>> priority
> >>>>>>>>>>>>>>>>> list
> >>>>>>>>>>>>>>>>>>> for
> >>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>> 1.8
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> release. I will try to update the document
> >> until
> >>>>>> mid
> >>>>>>>>>>>>>>>>> of
> >>>>>>>>>>>>>>>>>>>> next
> >>>>>>>>>>>>>>>>>>>>>>> week.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Regards,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Timo
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Am 27.11.18 um 08:08 schrieb Shuyi Chen:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks a lot, Xuefu. I was busy for some
> >> other
> >>>>>>>>>>>>>>>>> stuff
> >>>>>>>>>>>>>>>>>>> for
> >>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>> last 2
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> weeks,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> but we are definitely interested in moving
> >> this
> >>>>>>>>>>>>>>>>>>> forward.
> >>>>>>>>>>>>>>>>>>>> I
> >>>>>>>>>>>>>>>>>>>>>>> think
> >>>>>>>>>>>>>>>>>>>>>>>>> once
> >>>>>>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> unified connector API design [1] is done, we
> >>> can
> >>>>>>>>>>>>>>>>>>> finalize
> >>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>>>>>>>> design
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> as
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> well and start creating concrete subtasks to
> >>>>>>>>>>>>>>>>>>> collaborate
> >>>>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> implementation with the community.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Mon, Nov 26, 2018 at 7:01 PM Zhang, Xuefu
> >> <
> >>>>>>>>>>>>>>>>>>>>>>>>>> [hidden email]>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi Shuyi,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I'm wondering if you folks still have the
> >>>>>>>>>>>>>>>>> bandwidth
> >>>>>>>>>>>>>>>>>>>>> working
> >>>>>>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>>>>>>> this.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> We have some dedicated resource and like to
> >>> move
> >>>>>>>>>>>>>>>>>> this
> >>>>>>>>>>>>>>>>>>>>>> forward.
> >>>>>>>>>>>>>>>>>>>>>>>> We
> >>>>>>>>>>>>>>>>>>>>>>>>>> can
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> collaborate.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Xuefu
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>> ------------------------------------------------------------------
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 发件人：wenlong.lwl<[hidden email]>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 日 期：2018年11月05日 11:15:35
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 收件人：<[hidden email]>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 主 题：Re: [DISCUSS] Flink SQL DDL Design
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi, Shuyi, thanks for the proposal.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I have two concerns about the table ddl:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1. how about remove the source/sink mark
> >> from
> >>>>>> the
> >>>>>>>>>>>>>>>>>> ddl,
> >>>>>>>>>>>>>>>>>>>>>> because
> >>>>>>>>>>>>>>>>>>>>>>>> it
> >>>>>>>>>>>>>>>>>>>>>>>>> is
> >>>>>>>>>>>>>>>>>>>>>>>>>>> not
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> necessary, the framework determine the table
> >>>>>>>>>>>>>>>>>> referred
> >>>>>>>>>>>>>>>>>>>> is a
> >>>>>>>>>>>>>>>>>>>>>>>> source
> >>>>>>>>>>>>>>>>>>>>>>>>>> or a
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> sink
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> according to the context of the query using
> >>> the
> >>>>>>>>>>>>>>>>>> table.
> >>>>>>>>>>>>>>>>>>>> it
> >>>>>>>>>>>>>>>>>>>>>> will
> >>>>>>>>>>>>>>>>>>>>>>>> be
> >>>>>>>>>>>>>>>>>>>>>>>>>> more
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> convenient for use defining a table which
> >> can
> >>> be
> >>>>>>>>>>>>>>>>>> both
> >>>>>>>>>>>>>>>>>>> a
> >>>>>>>>>>>>>>>>>>>>>> source
> >>>>>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>>>> sink,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and more convenient for catalog to
> >> persistent
> >>>>>> and
> >>>>>>>>>>>>>>>>>>> manage
> >>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>> meta
> >>>>>>>>>>>>>>>>>>>>>>>>>>> infos.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 2. how about just keeping one pure string
> >> map
> >>> as
> >>>>>>>>>>>>>>>>>>>>> parameters
> >>>>>>>>>>>>>>>>>>>>>>> for
> >>>>>>>>>>>>>>>>>>>>>>>>>> table,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> like
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> create tabe Kafka10SourceTable (
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> intField INTEGER,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> stringField VARCHAR(128),
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> longField BIGINT,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> rowTimeField TIMESTAMP
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ) with (
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.type = ’kafka’,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.property-version = ’1’,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.version = ’0.10’,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.topic =
> >>> ‘test-kafka-topic’,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.startup-mode =
> >>>>>>>>>>>>>>>>> ‘latest-offset’,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties.specific-offset =
> >>> ‘offset’,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> format.type = 'json'
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> format.prperties.version=’1’,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> format.derive-schema = 'true'
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> );
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Because:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 1. in TableFactory, what user use is a
> >> string
> >>>>>> map
> >>>>>>>>>>>>>>>>>>>>>> properties,
> >>>>>>>>>>>>>>>>>>>>>>>>>> defining
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> parameters by string-map can be the closest
> >>> way
> >>>>>> to
> >>>>>>>>>>>>>>>>>>>> mapping
> >>>>>>>>>>>>>>>>>>>>>> how
> >>>>>>>>>>>>>>>>>>>>>>>>> user
> >>>>>>>>>>>>>>>>>>>>>>>>>>> use
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> parameters.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 2. The table descriptor can be extended by
> >>> user,
> >>>>>>>>>>>>>>>>>> like
> >>>>>>>>>>>>>>>>>>>> what
> >>>>>>>>>>>>>>>>>>>>>> is
> >>>>>>>>>>>>>>>>>>>>>>>> done
> >>>>>>>>>>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> Kafka
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and Json, it means that the parameter keys
> >> in
> >>>>>>>>>>>>>>>>>>> connector
> >>>>>>>>>>>>>>>>>>>> or
> >>>>>>>>>>>>>>>>>>>>>>>> format
> >>>>>>>>>>>>>>>>>>>>>>>>>> can
> >>>>>>>>>>>>>>>>>>>>>>>>>>> be
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> different in different implementation, we
> >> can
> >>>>>> not
> >>>>>>>>>>>>>>>>>>>> restrict
> >>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>> key
> >>>>>>>>>>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>>>>>>>> a
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> specified set, so we need a map in connector
> >>>>>> scope
> >>>>>>>>>>>>>>>>>>> and a
> >>>>>>>>>>>>>>>>>>>>> map
> >>>>>>>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> connector.properties scope. why not just
> >> give
> >>>>>>>>>>>>>>>>> user a
> >>>>>>>>>>>>>>>>>>>>> single
> >>>>>>>>>>>>>>>>>>>>>>> map,
> >>>>>>>>>>>>>>>>>>>>>>>>> let
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> them
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> put parameters in a format they like, which
> >> is
> >>>>>>>>>>>>>>>>> also
> >>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>> simplest
> >>>>>>>>>>>>>>>>>>>>>>>>> way
> >>>>>>>>>>>>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> implement DDL parser.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 3. whether we can define a format clause or
> >>> not,
> >>>>>>>>>>>>>>>>>>> depends
> >>>>>>>>>>>>>>>>>>>>> on
> >>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> implementation of the connector, using
> >>> different
> >>>>>>>>>>>>>>>>>>> clause
> >>>>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>>>>> may
> >>>>>>>>>>>>>>>>>>>>>>>>>>> make
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> a
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> misunderstanding that we can combine the
> >>>>>>>>>>>>>>>>> connectors
> >>>>>>>>>>>>>>>>>>> with
> >>>>>>>>>>>>>>>>>>>>>>>> arbitrary
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> formats,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> which may not work actually.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Sun, 4 Nov 2018 at 18:25, Dominik
> >> Wosiński
> >>> <
> >>>>>>>>>>>>>>>>>>>>>>> [hidden email]
> >>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> +1, Thanks for the proposal.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I guess this is a long-awaited change. This
> >>> can
> >>>>>>>>>>>>>>>>>>> vastly
> >>>>>>>>>>>>>>>>>>>>>>> increase
> >>>>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> functionalities of the SQL Client as it
> >> will
> >>> be
> >>>>>>>>>>>>>>>>>>>> possible
> >>>>>>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>>>>> use
> >>>>>>>>>>>>>>>>>>>>>>>>>>> complex
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> extensions like for example those provided
> >> by
> >>>>>>>>>>>>>>>>>> Apache
> >>>>>>>>>>>>>>>>>>>>>>> Bahir[1].
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Best Regards,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Dom.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> https://github.com/apache/bahir-flink
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> sob., 3 lis 2018 o 17:17 Rong Rong <
> >>>>>>>>>>>>>>>>>>>> [hidden email]>
> >>>>>>>>>>>>>>>>>>>>>>>>>> napisał(a):
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> +1. Thanks for putting the proposal
> >> together
> >>>>>>>>>>>>>>>>>> Shuyi.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL has been brought up in a couple of
> >> times
> >>>>>>>>>>>>>>>>>>>> previously
> >>>>>>>>>>>>>>>>>>>>>>> [1,2].
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Utilizing
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> DDL will definitely be a great extension
> >> to
> >>>>>> the
> >>>>>>>>>>>>>>>>>>>> current
> >>>>>>>>>>>>>>>>>>>>>>> Flink
> >>>>>>>>>>>>>>>>>>>>>>>>> SQL
> >>>>>>>>>>>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> systematically support some of the
> >>> previously
> >>>>>>>>>>>>>>>>>>> brought
> >>>>>>>>>>>>>>>>>>>> up
> >>>>>>>>>>>>>>>>>>>>>>>>> features
> >>>>>>>>>>>>>>>>>>>>>>>>>>> such
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> as
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]. And it will also be beneficial to see
> >>> the
> >>>>>>>>>>>>>>>>>>>> document
> >>>>>>>>>>>>>>>>>>>>>>>> closely
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> aligned
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> with the previous discussion for unified
> >> SQL
> >>>>>>>>>>>>>>>>>>> connector
> >>>>>>>>>>>>>>>>>>>>> API
> >>>>>>>>>>>>>>>>>>>>>>>> [4].
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I also left a few comments on the doc.
> >>> Looking
> >>>>>>>>>>>>>>>>>>> forward
> >>>>>>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>>>>>>> alignment
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> with the other couple of efforts and
> >>>>>>>>>>>>>>>>> contributing
> >>>>>>>>>>>>>>>>>> to
> >>>>>>>>>>>>>>>>>>>>> them!
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Best,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Rong
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> http://mail-archives.apache.org/mod_mbox/flink-dev/201805.mbox/%3CCAMZk55ZTJA7MkCK1Qu4gLPu1P9neqCfHZtTcgLfrFjfO4Xv5YQ%40mail.gmail.com%3E
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3CDC070534-0782-4AFD-8A85-8A82B384B8F7%40gmail.com%3E
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
> >>>>>>>>>>>>>>>>>>> https://issues.apache.org/jira/browse/FLINK-8003
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [4]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> http://mail-archives.apache.org/mod_mbox/flink-dev/201810.mbox/%3C6676cb66-6f31-23e1-eff5-2e9c19f88483@...%3E
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Fri, Nov 2, 2018 at 10:22 AM Bowen Li <
> >>>>>>>>>>>>>>>>>>>>>>> [hidden email]
> >>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks Shuyi!
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I left some comments there. I think the
> >>>>>> design
> >>>>>>>>>>>>>>>>> of
> >>>>>>>>>>>>>>>>>>> SQL
> >>>>>>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Flink-Hive
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration/External catalog enhancements
> >>>>>> will
> >>>>>>>>>>>>>>>>>> work
> >>>>>>>>>>>>>>>>>>>>>> closely
> >>>>>>>>>>>>>>>>>>>>>>>>> with
> >>>>>>>>>>>>>>>>>>>>>>>>>>> each
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> other. Hope we are well aligned on the
> >>>>>>>>>>>>>>>>> directions
> >>>>>>>>>>>>>>>>>>> of
> >>>>>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>> two
> >>>>>>>>>>>>>>>>>>>>>>>>>>> designs,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> and I
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> look forward to working with you guys on
> >>>>>> both!
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bowen
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On Thu, Nov 1, 2018 at 10:57 PM Shuyi
> >> Chen
> >>> <
> >>>>>>>>>>>>>>>>>>>>>>>> [hidden email]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> wrote:
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi everyone,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL DDL support has been a long-time ask
> >>>>>> from
> >>>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>>> community.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Current
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Flink
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SQL support only DML (e.g. SELECT and
> >>> INSERT
> >>>>>>>>>>>>>>>>>>>>>> statements).
> >>>>>>>>>>>>>>>>>>>>>>> In
> >>>>>>>>>>>>>>>>>>>>>>>>> its
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> current
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> form, Flink SQL users still need to
> >>>>>>>>>>>>>>>>>> define/create
> >>>>>>>>>>>>>>>>>>>>> table
> >>>>>>>>>>>>>>>>>>>>>>>>> sources
> >>>>>>>>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> sinks
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> programmatically in Java/Scala. Also, in
> >>> SQL
> >>>>>>>>>>>>>>>>>>> Client,
> >>>>>>>>>>>>>>>>>>>>>>> without
> >>>>>>>>>>>>>>>>>>>>>>>>> DDL
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> support,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the current implementation does not
> >> allow
> >>>>>>>>>>>>>>>>>>> dynamical
> >>>>>>>>>>>>>>>>>>>>>>> creation
> >>>>>>>>>>>>>>>>>>>>>>>>> of
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> table,
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> type
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> or functions with SQL, this adds
> >> friction
> >>>>>> for
> >>>>>>>>>>>>>>>>>> its
> >>>>>>>>>>>>>>>>>>>>>>> adoption.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I drafted a design doc [1] with a few
> >>> other
> >>>>>>>>>>>>>>>>>>>> community
> >>>>>>>>>>>>>>>>>>>>>>>> members
> >>>>>>>>>>>>>>>>>>>>>>>>>> that
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> proposes
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> the design and implementation for adding
> >>> DDL
> >>>>>>>>>>>>>>>>>>> support
> >>>>>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>>>>> Flink.
> >>>>>>>>>>>>>>>>>>>>>>>>>> The
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> initial
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> design considers DDL for table, view,
> >>> type,
> >>>>>>>>>>>>>>>>>>> library
> >>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>>> function.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> It
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> will
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> be great to get feedback on the design
> >>> from
> >>>>>>>>>>>>>>>>> the
> >>>>>>>>>>>>>>>>>>>>>> community,
> >>>>>>>>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> align
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> with
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> latest effort in unified SQL connector
> >> API
> >>>>>> [2]
> >>>>>>>>>>>>>>>>>> and
> >>>>>>>>>>>>>>>>>>>>> Flink
> >>>>>>>>>>>>>>>>>>>>>>>> Hive
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> integration
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3].
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Any feedback is highly appreciated.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Thanks
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Shuyi Chen
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [1]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit?usp=sharing
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [2]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> [3]
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> >>
> https://docs.google.com/document/d/1SkppRD_rE3uOKSN-LuZCqn4f7dz0zW5aa6T_hBZq5_o/edit?usp=sharing
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> --
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
> >>>>>>>>>>>>>>>>> somehow
> >>>>>>>>>>>>>>>>>>>>> connect
> >>>>>>>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>>>>>> your
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> future."
> >>>>>>>>>>>>>>>>>>>>>>>>>>> --
> >>>>>>>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will
> >> somehow
> >>>>>>>>>>>>>>>>> connect
> >>>>>>>>>>>>>>>>>> in
> >>>>>>>>>>>>>>>>>>>>> your
> >>>>>>>>>>>>>>>>>>>>>>>>> future."
> >>>>>>>>>>>>>>>>>>>>>> --
> >>>>>>>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow
> >>> connect
> >>>>>>> in
> >>>>>>>>>>> your
> >>>>>>>>>>>>>>>>>>>> future."
> >>>>>>>>>>>>>>>>> --
> >>>>>>>>>>>>>>>>> "So you have to trust that the dots will somehow connect
> >> in
> >>>>>>> your
> >>>>>>>>>>>>>>> future."
> >>>>>>>>>>>>>>>
> >>>>>>> --
> >>>>>>> "So you have to trust that the dots will somehow connect in your
> >>>> future."
> >>>>
> >>> --
> >>> "So you have to trust that the dots will somehow connect in your
> future."
> >>>
>
>

[Danny Chan]

Thanks for all you discussions Timo, Jark Wu, Lin Li, Fabian

I have fired a new design doc in [1] which reorganized from the MVP doc[2] and the initial doc[3] that both proposed by Shuyi Chen.

The main diff is that i extend the create table DDL to support complex sql type (array, map and struct), also i have added 3 points that need to reach a consensus：

1. Where we should put the parse code ? (blocking)
2. How to integrate the sql parse logic with TableEnvironment and SqlClient ? (blocking)
3. What format should should the table ddl with clause be like ? (non-blocking)

For points 1 and 2, i have put some solutions in [1], we need a duscussion because they are blocking, for 3 i have fired a new JIRA issue to track[4].

[1] https://docs.google.com/document/d/1OmVyuPk9ibGUC-CnPHbXvCg_fdG1TeC3lXSnqcUEYmM/edit?usp=sharing
[2] https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit
[3] https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit
[4] https://issues.apache.org/jira/browse/FLINK-12557

Best,
Danny Chan

>
> Thanks for all you discussions Timo, Jark Wu, Lin Li, Fabian
>
> I have fired a new design doc in [1] which is reorganized from the MVP doc[2] and the initial doc[3] that both proposed by Shuyi Chen.
>
> The main diff is that i extend the create table DDL to support complex sql type (array, map and struct), also i have added 3 points that need to reach a consensus：
>
> 1. Where we should put the parse code ? (blocking)
> 2. How to integrate the sql parse logic with TableEnvironment and SqlClient ? (blocking)
> 3. What format should the table ddl with clause be like ? (non-blocking)
>
> For points 1 and 2, i have put some solutions in [1] (highlight title as red), we need a duscussion because they are blocking, for 3 i have fired a new JIRA issue to track[4].
>
> [1] https://docs.google.com/document/d/1OmVyuPk9ibGUC-CnPHbXvCg_fdG1TeC3lXSnqcUEYmM/edit?usp=sharing
> [2] https://docs.google.com/document/d/1ug1-aVBSCxZQk58kR-yaK2ETCgL3zg0eDUVGCnW2V9E/edit
> [3] https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit
> [4] https://issues.apache.org/jira/browse/FLINK-12557