Fix generation of EC join conditions at the wrong plan level. get_baserel_parampathinfo previously assumed without checking that the results of generate_join_implied_equalities "necessarily satisfy join_clause_is_movable_into". This turns out to be wrong in the presence of outer joins, because the generated clauses could include Vars that mustn't be evaluated below a relevant outer join. That led to applying clauses at the wrong plan level and possibly getting incorrect query results. We must check each clause's nullable_relids, and really the right thing to do is test join_clause_is_movable_into.
However, trying to fix it that way exposes an oversight in equivclass.c: it wasn't careful about marking join clauses for appendrel children with the correct clause_relids. That caused the modified get_baserel_parampathinfo code to reject some clauses it still needs to accept. (See parallel commit for HEAD/v16 for more commentary about that.) Per bug #18429 from Benoît Ryder. This misbehavior existed for a long time before commit 2489d76c4, so patch v12-v15 this way. Discussion: https://postgr.es/m/18429-8982d4a348cc8...@postgresql.org Branch ------ REL_14_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/ab2402268c04401533f163d959cdccd0e124f526 Modified Files -------------- src/backend/optimizer/path/equivclass.c | 15 +++++++++++++++ src/backend/optimizer/util/relnode.c | 25 ++++++++++++++++++------- src/test/regress/expected/join.out | 31 +++++++++++++++++++++++++++++++ src/test/regress/sql/join.sql | 19 +++++++++++++++++++ 4 files changed, 83 insertions(+), 7 deletions(-)
