You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@flink.apache.org by "Aljoscha Krettek (Jira)" <ji...@apache.org> on 2020/04/09 15:28:00 UTC
[jira] [Created] (FLINK-17074) Deprecate DataStream.keyBy() that
use tuple/expression keys
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)