Build EC members for child join rels in the right memory context.
This patch prevents crashes or wrong plans when partition-wise joins
are considered during GEQO planning, as a consequence of the
EquivalenceClass data structures becoming corrupt after a GEQO
context reset.
A remaining problem is that successive GEQO cycles will make multiple
copies of the required EC members, since add_child_join_rel_equivalences
has no idea that such members might exist already. For now we'll just
live with that. The lack of field complaints of crashes suggests that
this is a mighty little-used situation.
Back-patch to v12 where this code was introduced.
Discussion: https://postgr.es/m/1683100.1601860653@sss.pgh.pa.us
Branch
------
REL_12_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/3d69efc4f07d773329dfbd39d6ec67a025cf7339
Modified Files
--------------
src/backend/optimizer/path/equivclass.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
