[jira] [Commented] (CALCITE-2807) Identify expanded IS NOT DISTINCT FROM expression when pushing down filter past join

["Julian Hyde (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-2807?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16845282#comment-16845282 ] 

Julian Hyde commented on CALCITE-2807:
--------------------------------------

Commit message is unclear. INDF is jargon.

> Identify expanded IS NOT DISTINCT FROM expression when pushing down filter past join
> ------------------------------------------------------------------------------------
>
>                 Key: CALCITE-2807
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2807
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>            Reporter: Laurent Goujon
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> IS NOT DISTINCT FROM expressions in join condition might actually be considered as equi-join conditions, and RelOptUtil#splitJoinConditions() has support for it. But some other join related functions/rules don't.
> One of them is RelOptUtil#pushDownJoinConditions (used by JoinPushExpressionsRule) which tries to push filter expressions below the join, but ends up modifying the join expression in a way which makes identify an IDNF condition impossible later.
> For example expression OR(AND(IS_NULL($1), IS_NULL($4)), EQUALS($1,$4)) will be changed into OR(AND($3, $6), EQUALS($1, $5)) which makes it harder/impossible for RelOptUtil#splitJoinConditions() to identify an IS NOT DISTINCT FROM equi-join condition.
> This is a variant of CALCITE-2803



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