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https://issues.apache.org/jira/browse/FLINK-13392?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17328387#comment-17328387
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Flink Jira Bot commented on FLINK-13392:
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This major issue is unassigned and itself and all of its Sub-Tasks have not
been updated for 30 days. So, it has been labeled "stale-major". If this ticket
is indeed "major", please either assign yourself or give an update. Afterwards,
please remove the label. In 7 days the issue will be deprioritized.
> WindowAggregate inherited from Aggregate incorrectly
> ----------------------------------------------------
>
> Key: FLINK-13392
> URL: https://issues.apache.org/jira/browse/FLINK-13392
> Project: Flink
> Issue Type: Improvement
> Components: Table SQL / Planner
> Reporter: Hequn Cheng
> Priority: Major
> Labels: stale-major
>
> As discussed in FLINK-12249, the WindowAggregate inherited from Aggregate
> incorrectly.
> For WindowAggregate, the group keys are window group and normal fields (may
> be empty), while Aggregate only has normal group keys part, and know nothing
> about window group key. Currently, many planner rules match and apply
> transformations on Aggregate, however some of them does not applicable to
> WindowAggregate, e.g. AggregateJoinTransposeRule, AggregateProjectMergeRule,
> etc.
> Although FLINK-12249 fixes the type equivalence check problem, we should do a
> step further to correct the WindowAggregate behavior. There are three options
> now:
> # make Aggregate's group key supports expressions(such as RexCall), not
> field reference only. and then the window group expression could be as a part
> of Aggregate's group key. the disadvantage is we must update all existing
> aggregate rules, metadata handlers, etc.
> # make WindowAggregate extends from SingleRel, not from Aggregate. the
> disadvantage is we must implement related planner rules about WindowAggregate.
> # in logical phase, we does not merge Aggregate and Project (with window
> group) into WindowAggregate, and convert the Project to a new kind of node
> named WindowAssigner, which could prevent Project from being pushed
> down/merged. and in physical phase, we merge them into WindowAggregate. the
> advantage is we could reuse current aggregate rules, and the disadvantage is
> we should add new rules about WindowAssigner.
> We could have some further discussions in the jira ticket.
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