From d6a8a29ac2bca06d4466e449f13d0cc52220714b Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 28 Jul 2015 13:20:40 -0400 Subject: Remove an unsafe Assert, and explain join_clause_is_movable_into() better. join_clause_is_movable_into() is approximate, in the sense that it might sometimes return "false" when actually it would be valid to push the given join clause down to the specified level. This is okay ... but there was an Assert in get_joinrel_parampathinfo() that's only safe if the answers are always exact. Comment out the Assert, and add a bunch of commentary to clarify what's going on. Per fuzz testing by Andreas Seltenreich. The added regression test is a pretty silly query, but it's based on his crasher example. Back-patch to 9.2 where the faulty logic was introduced. --- src/backend/optimizer/util/relnode.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'src/backend/optimizer/util/relnode.c') diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index edbe6252408..7e4cd64d9b9 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -931,9 +931,18 @@ get_joinrel_parampathinfo(PlannerInfo *root, RelOptInfo *joinrel, { RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc); + /* + * In principle, join_clause_is_movable_into() should accept anything + * returned by generate_join_implied_equalities(); but because its + * analysis is only approximate, sometimes it doesn't. So we + * currently cannot use this Assert; instead just assume it's okay to + * apply the joinclause at this level. + */ +#ifdef NOT_USED Assert(join_clause_is_movable_into(rinfo, joinrel->relids, join_and_req)); +#endif if (!join_clause_is_movable_into(rinfo, outer_path->parent->relids, outer_and_req) && -- cgit v1.2.3