diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index b80427f041e..c999fb6419c 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.142 2008/10/21 20:42:53 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.143 2008/12/08 00:16:09 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1098,6 +1098,12 @@ convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink, return false; /* + * The subquery must have a nonempty jointree, else we won't have a join. + */ + if (subselect->jointree->fromlist == NIL) + return false; + + /* * Separate out the WHERE clause. (We could theoretically also remove * top-level plain JOIN/ON clauses, but it's probably not worth the * trouble.) @@ -1180,6 +1186,7 @@ convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink, /* Identify all the rels syntactically within the subselect */ subselect_varnos = get_relids_in_jointree((Node *) subselect->jointree, true); + Assert(!bms_is_empty(subselect_varnos)); Assert(bms_is_subset(right_varnos, subselect_varnos)); /* Now we can attach the modified subquery rtable to the parent */ |