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Back-patch fix to copy sub-Query nodes before planning them. This

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fixes problems with subselects appearing in contexts like COALESCE or
BETWEEN, where parser will make multiple links to same subexpression.
This commit is contained in:
Tom Lane 2000-09-23 21:00:05 +00:00
parent c3aab02939
commit 3017000115
1 changed files with 15 additions and 4 deletions
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19
src/backend/optimizer/plan/subselect.c
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@ -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 $
*
*-------------------------------------------------------------------------
*/
@ -136,13 +136,24 @@ 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