From e76913802c5347831aadc1513b59196bde6ec116 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 4 Dec 2022 13:48:12 -0500 Subject: [PATCH] Fix broken MemoizePath support in reparameterize_path(). It neglected to recurse to the subpath, meaning you'd get back a path identical to the input. This could produce wrong query results if the omission meant that the subpath fails to enforce some join clause it should be enforcing. We don't have a test case for this at the moment, but the code is obviously broken and the fix is equally obvious. Back-patch to v14 where Memoize was introduced. Richard Guo Discussion: https://postgr.es/m/CAMbWs4_R=ORpz=Lkn2q3ebPC5EuWyfZF+tmfCPVLBVK5W39mHA@mail.gmail.com --- src/backend/optimizer/util/pathnode.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c index ea2e158f6d428..5379c087a1f01 100644 --- a/src/backend/optimizer/util/pathnode.c +++ b/src/backend/optimizer/util/pathnode.c @@ -3994,9 +3994,15 @@ reparameterize_path(PlannerInfo *root, Path *path, case T_Memoize: { MemoizePath *mpath = (MemoizePath *) path; + Path *spath = mpath->subpath; + spath = reparameterize_path(root, spath, + required_outer, + loop_count); + if (spath == NULL) + return NULL; return (Path *) create_memoize_path(root, rel, - mpath->subpath, + spath, mpath->param_exprs, mpath->hash_operators, mpath->singlerow,