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Aljoscha Krettek closed FLINK-17074. ------------------------------------ Resolution: Done master: 4f106c50194886cb6e98b993785481192485479c..db3c3418edee55f103bec3bf0ce9caffc947d2da > 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, API / Scala > Reporter: Aljoscha Krettek > Assignee: Etienne Chauchot > Priority: Major > Labels: pull-request-available, starter > Fix For: 1.11.0 > > > 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. -- This message was sent by Atlassian Jira (v8.3.4#803005)