opt: minor fix for ExtractJoinEquality rule #44788
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The `ExtractJoinEquality` rule does not fire if one of the equality sides are `ConstValue`. But it is possible for an expression to have no outer columns without it being a constant value (e.g. because constant folding failed). In this case the rule gets confused and incorrectly pushes down a projection to the wrong side. Fixes cockroachdb#44746. Release note (bug fix): fixed a "cannot map variable" error in some rare cases involving joins.
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Reviewed 3 of 3 files at r1.
Reviewable status:complete! 1 of 0 LGTMs obtained (waiting on @andy-kimball)
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44788: opt: minor fix for ExtractJoinEquality rule r=RaduBerinde a=RaduBerinde The `ExtractJoinEquality` rule does not fire if one of the equality sides are `ConstValue`. But it is possible for an expression to have no outer columns without it being a constant value (e.g. because constant folding failed). In this case the rule gets confused and incorrectly pushes down a projection to the wrong side. Fixes #44746. Release note (bug fix): fixed a "cannot map variable" error in some rare cases involving joins. Thanks to @mrigger for finding this bug. Co-authored-by: Radu Berinde <radu@cockroachlabs.com>
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The
ExtractJoinEqualityrule does not fire if one of the equalitysides are
ConstValue. But it is possible for an expression to haveno outer columns without it being a constant value (e.g. because
constant folding failed). In this case the rule gets confused and
incorrectly pushes down a projection to the wrong side.
Fixes #44746.
Release note (bug fix): fixed a "cannot map variable" error in some
rare cases involving joins.
Thanks to @mrigger for finding this bug.