[jira] [Assigned] (FLINK-23663) Reduce state size in ChangelogNormalize through filter push down

["Ingo Bürk (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-23663?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ingo Bürk reassigned FLINK-23663:
---------------------------------

    Assignee: Ingo Bürk

> Reduce state size in ChangelogNormalize through filter push down
> ----------------------------------------------------------------
>
>                 Key: FLINK-23663
>                 URL: https://issues.apache.org/jira/browse/FLINK-23663
>             Project: Flink
>          Issue Type: Improvement
>          Components: Table SQL / Planner
>            Reporter: Timo Walther
>            Assignee: Ingo Bürk
>            Priority: Major
>
> {{ChangelogNormalize}} is an expensive stateful operation as it stores data for each key. 
> Filters are generally not pushed through a ChangelogNormalize node which means that users have no possibility to at least limit the key space. Pushing filters like {{a < 10}} into a source like {{upsert-kafka}} that is emitting {{+I[key1, a=9]}} and {{-D[key1, a=10]}}, is problematic as the deletion will be filtered and leads to wrong results. But limiting the filter push down to key space should be safe.
> Furthermore, it seems the current implementation is also wrong as it pushes any kind of filter through {{ChangelogNormalize}} but only if the source implements filter push down.



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