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https://issues.apache.org/jira/browse/FLINK-7471?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16137343#comment-16137343
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Fabian Hueske commented on FLINK-7471:
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I understand the motivation for this issue and agree that it would be good to
support non-retractable UDAGGs for bounded OVER aggregations.
My question is rather what happens if we have a mix of retractable and
non-retractable aggregation functions? Are the retractable functions
efficiently computed or not?
Treating all aggregation functions as non-retractable might introduce a
significant and unnecessary performance penalty. Think a of a query with
several retractable aggregations and then adding one non-retractable UDAGG.
Handling retractable and non-retractable aggregation functions separately would
mean to add quite a bit of additional logic. For example, we would need to
extend the {{GeneratedAggregations}} interface to account for "empty" fields in
the output record which would be filled by the other aggregation logic.
> Improve bounded OVER support non-retract method AGG
> ---------------------------------------------------
>
> Key: FLINK-7471
> URL: https://issues.apache.org/jira/browse/FLINK-7471
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Reporter: sunjincheng
> Assignee: sunjincheng
>
> Currently BOUNDED OVER WINDOW only support have {{retract}} method AGG. In
> this JIRA. will add non-retract method support.
> What do you think? [~fhueske]
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