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https://issues.apache.org/jira/browse/CALCITE-3373?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16938218#comment-16938218
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Wang Yanlin commented on CALCITE-3373:
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I think this is a more direct way to generate semi-join.
Just a little concern, might this have back compatibility issues if change
in/exist to semi join directly?
For some cases, user may have already change in/exist to inner join, and
process without the second step, ie SemiJoinRule.
So, should we have a configuration or same other way to control whether to
transform in/exist to semi join?
> Decorrelate boolean context IN or existential subquery directly into
> SEMI/ANTI join
> -----------------------------------------------------------------------------------
>
> Key: CALCITE-3373
> URL: https://issues.apache.org/jira/browse/CALCITE-3373
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: jin xing
> Priority: Major
>
> The current approach to generate semi-join from IN/EXISTS is as below:
> # Decorrelation
> # Transforming by SemiJoinRule to get a semi-join
> A more straightforward approach is to generate the semi-join right in
> Decorrelation.
> What's more, we should also have an approach to generate anti-join right in
> Decorrelation.(Currently there's no analogous rule to SemiJoinRule for
> anti-join)
> This one is related to CALCITE-3367
>
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