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Posted to issues@calcite.apache.org by "Forward Xu (Jira)" <ji...@apache.org> on 2019/09/26 01:45:00 UTC
[jira] [Commented] (CALCITE-3372) Add a rule to transform a
semijoin into a join on top of aggregate
[ https://issues.apache.org/jira/browse/CALCITE-3372?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16938175#comment-16938175 ]
Forward Xu commented on CALCITE-3372:
-------------------------------------
hi [~hyuan] I'd like to try that.
> Add a rule to transform a semijoin into a join on top of aggregate
> ------------------------------------------------------------------
>
> Key: CALCITE-3372
> URL: https://issues.apache.org/jira/browse/CALCITE-3372
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Haisheng Yuan
> Priority: Major
>
> {code:java}
> Semijoin
> |- TS1
> +- TS2
> {code}
> can be transformed into
> {code:java}
> Project
> +-InnerJoin
> |- TS1
> +- Aggregate
> + TS2
> {code}
> We may benefit from the new plan by join relation reordering if TS2 is large even after aggregation.
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