PR #90599 - xform: derive implicit predicates from FK constraint for lookup join

[cockroach-teamcity]

Exalate commented:

Related PR: cockroachdb/cockroach#90599
Commit: cockroachdb/cockroach@aaa6876

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Release note (performance improvement): This patch enables more
efficient lookup joins by deriving new join constraints when
equijoin predicates exist on the column(s) of a unique constraint on one
table which are a proper subset of the referencing columns of a foreign
key constraint on the other table. If an index exists on those FK
constraint referencing columns, equijoin predicates are derived between
the PK and FK columns not currently bound by ON clause predicates.

Jira Issue: DOC-6158