diff options
| author | Tom Lane | 2000-09-23 21:00:05 +0000 |
|---|---|---|
| committer | Tom Lane | 2000-09-23 21:00:05 +0000 |
| commit | 3017000115e06d4864526bd60d097308849491d2 (patch) | |
| tree | 14dc796d14c04ccee1f0470213ba6ea7a9e5ad66 | |
| parent | c3aab02939ef7bca0d7918e68b7aea3c10ff5ae5 (diff) | |
Back-patch fix to copy sub-Query nodes before planning them. This
fixes problems with subselects appearing in contexts like COALESCE or
BETWEEN, where parser will make multiple links to same subexpression.
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index 373b05d42fe..29e4a69c2d1 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 - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.36 2000/04/14 00:19:16 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.36.2.1 2000/09/23 21:00:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -136,14 +136,25 @@ make_subplan(SubLink *slink) PlannerQueryLevel++; /* we become child */ - /* Check to see if this node was already processed; if so we have - * trouble. Someday should change tree representation so that we can - * cope with multiple links to the same subquery, but for now... + /* + * Check to see if this node was already processed; if so we have + * trouble. We check to see if the linked-to Query appears to have + * been planned already, too. */ if (subquery == NULL) + elog(ERROR, "make_subplan: invalid expression structure (SubLink already processed?)"); + if (subquery->base_rel_list != NIL) elog(ERROR, "make_subplan: invalid expression structure (subquery already processed?)"); /* + * Copy the source Query node. This is a quick and dirty kluge to resolve + * the fact that the parser can generate trees with multiple links to the + * same sub-Query node, but the planner wants to scribble on the Query. + * Try to clean this up when we do querytree redesign... + */ + subquery = (Query *) copyObject(subquery); + + /* * For an EXISTS subplan, tell lower-level planner to expect that only * the first tuple will be retrieved. For ALL and ANY subplans, we * will be able to stop evaluating if the test condition fails, so |