From 95f4e59c3286671656aff7db45b322f14a7bb8cc Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 28 Jul 2015 13:20:39 -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 be2ef3becfe..68a93a1a5bd 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -982,9 +982,18 @@ 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