release-20.2: opt: allow IN subquery to be converted to lookup join #63869
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We like to assume that the result of building a memo with placeholders followed by AssignPlaceholders is equivalent to building the query with the values directly. This is not necessarily the case - it is possible that some normalization rules act on a higher part of the tree in a way that would not happen if we had fully normalized a lower part of the tree. This commit adds two new opttester directives: `assign-placeholders-norm` and `assign-placeholders-opt`. These take a query that has placeholders and simulates the prepared query planning path. We use these facilities to add some tests that reproduce a customer issue. Release note: None
This change adds a rule that handles a case which prevents Exists subqueries from becoming lookup joins. Fixes cockroachdb#43198. Release note (performance improvement): certain queries containing `<tuple> IN (<subquery>)` conditions may run significantly faster.
RaduBerinde
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mgartner
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Apr 19, 2021
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Reviewed 4 of 4 files at r1, 5 of 5 files at r2.
Reviewable status:complete! 0 of 0 LGTMs obtained (waiting on @rytaft)
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Backport 2/2 commits from #63780.
/cc @cockroachdb/release
opt: add opttester facility to test placeholder assignment
We like to assume that the result of building a memo with placeholders
followed by AssignPlaceholders is equivalent to building the query
with the values directly. This is not necessarily the case - it is
possible that some normalization rules act on a higher part of the
tree in a way that would not happen if we had fully normalized a lower
part of the tree.
This commit adds two new opttester directives:
assign-placeholders-normandassign-placeholders-opt. These take aquery that has placeholders and simulates the prepared query planning
path.
We use these facilities to add some tests that reproduce a customer
issue.
Release note: None
opt: allow IN subquery to be converted to lookup join
This change adds a rule that handles a case which prevents Exists
subqueries from becoming lookup joins.
Fixes #43198.
Release note (performance improvement): certain queries containing
<tuple> IN (<subquery>)conditions may run significantly faster.