[jira] [Created] (FLINK-17074) Deprecate DataStream.keyBy() that use tuple/expression keys

[Shang Yuanchun (Jira)]

Aljoscha Krettek created FLINK-17074:
----------------------------------------

             Summary: Deprecate DataStream.keyBy() that use tuple/expression keys
                 Key: FLINK-17074
                 URL: https://issues.apache.org/jira/browse/FLINK-17074
             Project: Flink
          Issue Type: Improvement
          Components: API / DataStream
         Environment: Currently you can either specify a {{KeySelector}}, tuple positions, and expression keys? I think {{KeySelectors}} are strictly superior and with lambdas (or function references) quite easy to use.  Tuple/expression keys use reflection underneath to do the field accesses, so performance is strictly worse. Also, when using a {{KeySelector}} you will have a meaningful key type {{KEY}} in your operations while for tuple/expression keys the key type is simply {{Tuple}}.

Tuple/expression keys were introduced before Java got support for lambdas in Java 8 and before we added the Table API. Nowadays, using a lambda is little more typing than using an expression key but is (possibly) faster and more type safe. The Table API should be used for these more expression-based/relational use cases.
            Reporter: Aljoscha Krettek






--
This message was sent by Atlassian Jira
(v8.3.4#803005)