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Don't crash if subquery appears multiple times in jointree. This should

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not happen anyway, but let's try not to get completely confused if it does
(due to rewriter bugs or whatever).
This commit is contained in:
Tom Lane 2001-01-27 04:42:32 +00:00
parent 352871ac93
commit f44639e1bf
1 changed files with 10 additions and 3 deletions
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13
src/backend/optimizer/plan/planner.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.100 2001/01/24 19:42:59 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.101 2001/01/27 04:42:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -279,7 +279,13 @@ pull_up_subqueries(Query *parse, Node *jtnode)
/*
* First, recursively pull up the subquery's subqueries,
* so that this routine's processing is complete for its
* jointree and rangetable.
* jointree and rangetable. NB: if the same subquery is
* referenced from multiple jointree items (which can't happen
* normally, but might after rule rewriting), then we will invoke
* this processing multiple times on that subquery. OK because
* nothing will happen after the first time. We do have to be
* careful to copy everything we pull up, however, or risk
* having chunks of structure multiply linked.
*/
subquery->jointree = (FromExpr *)
pull_up_subqueries(subquery, (Node *) subquery->jointree);
@ -288,7 +294,8 @@ pull_up_subqueries(Query *parse, Node *jtnode)
* no adjustments will be needed in the subquery's rtable).
*/
rtoffset = length(parse->rtable);
parse->rtable = nconc(parse->rtable, subquery->rtable);
parse->rtable = nconc(parse->rtable,
copyObject(subquery->rtable));
/*
* Make copies of the subquery's jointree and targetlist
* with varnos adjusted to match the merged rangetable.