Laurent Goujon created CALCITE-2807:
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Summary: 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
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 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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