[jira] [Created] (CALCITE-2803) Identify expanded IS NOT DISTINCT FROM expression when pushing project past join

["Laurent Goujon (JIRA)" <ji...@apache.org>]

Laurent Goujon created CALCITE-2803:
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             Summary: Identify expanded IS NOT DISTINCT FROM expression when pushing project past join
                 Key: CALCITE-2803
                 URL: https://issues.apache.org/jira/browse/CALCITE-2803
             Project: Calcite
          Issue Type: Improvement
          Components: core
            Reporter: Laurent Goujon
            Assignee: Julian Hyde


{{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 {{ProjectJoinTransposeRule}} which tries to push project expressions below the join, but ends up modifying the join expression too by pushing complex expression below/

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.



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