[ANNOUNCE] Weekly Community Update 2019/49

[Konstantin Knauf-3]

Dear community,

happy to share this week's community digest with an update on Flink 1.8.3,
a revival of the n-ary stream operator, a proposal to move our build
infrastructure to Azure pipelines, and quite a few other topics. Enjoy.

Flink Development
==============

* [releases] The feature freeze for *Flink 1.10* is tonight.

* [releases] Hequn has published and started a vote on RC3 for *Flink 1.8.3
*Voting is open until Dec. 10th 2019, 16:00 UTC. No votes so far, but I
assume this will change after the feature freeze. [1]

* [runtime] Piotr has restarted the discussion to add an *n-ary stream
operator* which would help to support multi-broadcast joins in Flink SQL
(think of a star schema). The topic has been discussed before (in 2016) in
the context of side-inputs and there is already an old design document
drafted by Aljoscha to build on top. [2]

* [connectors] Chesnay started a conversation to drop support for *Kafka
0.8/0.9* connectors in the upcoming release. It seems that quite a few
people are in favor of dropping, but Becket also made a valid point to only
deprecate these connector instead of removing them all togehter. [3]

* [connectors] Becket has started the vote on *FLIP-27, the new source
interface.* This has been a long ongoing topic, but it has not been
officially been voted on so far. So there we go. [4,5]

* [state backends] Stephan has proposed to drop support for the *synchronous
mode of the heap statebackend.* One supporting comment so far. [6]

* [hadoop] Craig Foster brought up the topic of *Hadoop 3* support in
Apache Flink*.* There is currently no one working on this topic, but Marton
Balassi of Cloudera reported that they have been working on this internally
and would be willing to contribute their work back next year. [7]

* [development process] There is currently no *end-to-end test for Flink
deployments on Mesos*. Yangze suggests to such tests now and has started a
discussion thread on the topic. He is now looking for feedback from Mesos
production users in order to improve the planned test suite. It seems the
community will need to maintain their own Mesos docker images for these
tests due to Java compatibility issues with the official Mesos docker
images. [8]

* [development process] Dawid has asked comitters to only vote with
their *apache.org
<http://apache.org> email* addresses and to only count these votes as
binding going forward. Only for apache.org addresses it is possible to
verify the status of the voter. [9]

* [development process] Following the discussion on reducing the build time
of Apache Flink, Robert and others did some experiments to migrate our
build from *Travis CI to Azure Pipelines. *In this thread [10] and wiki
page [11] he presents his results and asks for opinions on how to move
forward. So far there has been a lot of positive feedback to migrate to
Azure pipelines mainly motivated by lower build times (due to additional
sponsored machines) and richer features.

[1]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/VOTE-Release-1-8-3-release-candidate-3-tp35628.html
[2]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Add-N-Ary-Stream-Operator-tp11341p35554.html
[3]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Drop-Kafka-0-8-0-9-tp35553.html
[4]
https://cwiki.apache.org/confluence/display/FLINK/FLIP-27%3A+Refactor+Source+Interface
[5]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/VOTE-FLIP-27-Refactor-Source-Interface-tp35569.html
[6]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Drop-Heap-Backend-Synchronous-snapshots-tp35621.html
[7]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/Re-Building-with-Hadoop-3-tp35522p35528.html
[8]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Adding-e2e-tests-for-Flink-s-Mesos-integration-tp35660p35687.html
[9]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Voting-from-apache-org-addresses-tp35499.html
[10]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-Migrate-build-infrastructure-from-Travis-CI-to-Azure-Pipelines-tp35538.html
[11]
https://cwiki.apache.org/confluence/display/FLINK/%5Bpreview%5D+Azure+Pipelines

Notable Bugs
==========

* [FLINK-15063] [1.9.1] The scope of the input/output metrics of the
network stack are interchanged, e.g. the outPoolUsage metric can be found
under task level scope of "shuffle.netty.input" instead of
"shuffle.netty.output". Fixed for 1.9.2. [12]

* [FLINK-14949] [1.9.1] [1.8.2] A job can get stuck during cancellation,
e.g. if Flink can not spawn the threads, which perform exactly this
cancellation. Fixed for 1.9.2 [13]

[12] https://issues.apache.org/jira/browse/FLINK-15063
[13] https://issues.apache.org/jira/browse/FLINK-14949

Events, Blog Posts, Misc
===================

* *Markos* and *Yuan* have published a recap of Flink Forward Asia 2019 on
the Ververica blog including a short summary of the keynotes. [14]

* Upcoming Meetups
    * On December 17th there will be the second Apache Flink meetup in
Seoul. [15] *Dongwon* has shared a detailed agenda in last weeks community
update. [16]

[14] https://www.ververica.com/blog/flink-forward-asia-2019-summary
[15] https://www.meetup.com/Seoul-Apache-Flink-Meetup/events/266824815/
[16]
http://apache-flink-mailing-list-archive.1008284.n3.nabble.com/ANNOUNCE-Weekly-Community-Update-2019-48-td35423.html

Cheers,

Konstantin (@snntrable)

--

Konstantin Knauf | Solutions Architect

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