From 8e24e517fc13f2ef55aead6d41cb7aa63fe1b817 Mon Sep 17 00:00:00 2001 From: Evdokimov Ilia Date: Thu, 23 Jul 2026 13:39:17 +0300 Subject: [PATCH v2 6/9] Apply the interestingness filter in the SEMI/ANTI join uniquekeys path The JOIN_SEMI/JOIN_ANTI branch of populate_joinrel_uniquekeys() copied the outer side's uniquekeys through unfiltered, skipping the is_uniquekey_useful_afterjoin() check that every other join type already goes through a few lines below when combining uniquekeys for the joinrel. Without the filter, uniquekeys that are no longer of any use (not needed for DISTINCT, not a singlerow marker, not useful for further merging) keep accumulating unpruned through chains of semi/anti joins -- a common shape for flattened IN/EXISTS subqueries. --- src/backend/optimizer/path/uniquekey.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/src/backend/optimizer/path/uniquekey.c b/src/backend/optimizer/path/uniquekey.c index f9d5ddeaf0f..ccbcf8258a2 100644 --- a/src/backend/optimizer/path/uniquekey.c +++ b/src/backend/optimizer/path/uniquekey.c @@ -670,11 +670,17 @@ populate_joinrel_uniquekeys(PlannerInfo *root, RelOptInfo *joinrel, { foreach(lc, outerrel->uniquekeys) { + UniqueKey *outer_ukey = lfirst(lc); + /* * the uniquekey on the outer side is not changed after semi/anti - * join. + * join, but still apply the same interestingness filter as the + * general inner/outer join path below, so uniquekeys that are + * of no further use don't keep accumulating through chains of + * semi/anti joins. */ - joinrel->uniquekeys = lappend(joinrel->uniquekeys, lfirst(lc)); + if (is_uniquekey_useful_afterjoin(root, outer_ukey, joinrel)) + joinrel->uniquekeys = lappend(joinrel->uniquekeys, outer_ukey); } return; } -- 2.34.1