From 30ec1cd56f65ff8a37bc79bda88c59cbe4103100 Mon Sep 17 00:00:00 2001 From: Evdokimov Ilia Date: Thu, 23 Jul 2026 13:50:32 +0300 Subject: [PATCH v2 7/9] Call populate_joinrel_uniquekeys() only when a joinrel is first built populate_joinrel_uniquekeys() was called unconditionally from make_join_rel() on every call, including when build_join_rel() returns an already-built joinrel from a different join-order decomposition of the same relid set (find_join_rel()'s cache hit path). populate_joinrel_uniquekeys() isn't idempotent -- it unconditionally appends -- so wide join queries, where the same relid set is legitimately reached via multiple decompositions, accumulated duplicate/redundant uniquekeys on the shared joinrel every time. Move the call inside build_join_rel()'s "build a new one" branch instead, alongside the rest of the one-time joinrel setup (tlist, direct_lateral_relids, has_eclass_joins, etc). It's now called exactly once per distinct joinrel, the same as everything else there. --- src/backend/optimizer/path/joinrels.c | 2 -- src/backend/optimizer/util/relnode.c | 11 +++++++++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c index fe58f7a928f..443e2dca7c0 100644 --- a/src/backend/optimizer/path/joinrels.c +++ b/src/backend/optimizer/path/joinrels.c @@ -756,8 +756,6 @@ make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2) sjinfo, pushed_down_joins, &restrictlist); - populate_joinrel_uniquekeys(root, joinrel, rel1, rel2, restrictlist, sjinfo->jointype); - /* * If we've already proven this join is empty, we needn't consider any * more paths for it. diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index beb55a5910a..4fbe266c647 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -946,6 +946,17 @@ build_join_rel(PlannerInfo *root, *restrictlist_ptr = restrictlist; build_joinrel_joinlist(joinrel, outer_rel, inner_rel); + /* + * Compute the joinrel's uniquekeys here, where we know this is the + * first (and only) time this particular joinrel is being built -- + * find_join_rel() above returns the same cached RelOptInfo for every + * later decomposition that produces the same relids, and + * populate_joinrel_uniquekeys() is not idempotent against being called + * more than once on the same joinrel (it unconditionally appends). + */ + populate_joinrel_uniquekeys(root, joinrel, outer_rel, inner_rel, + restrictlist, sjinfo->jointype); + /* * This is also the right place to check whether the joinrel has any * pending EquivalenceClass joins. -- 2.34.1