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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2001-01-27 04:42:32 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2001-01-27 04:42:32 +0000 |
| commit | f44639e1bf87c317c51e6882bef035614f25c7e6 (patch) | |
| tree | c94454e0001eba37cb43267a0cd9f234807166bc | |
| parent | 352871ac9338e856b9a1cb7783148e6ac80dd84a (diff) | |
| download | postgresql-f44639e1bf87c317c51e6882bef035614f25c7e6.tar.gz postgresql-f44639e1bf87c317c51e6882bef035614f25c7e6.zip | |
Don't crash if subquery appears multiple times in jointree. This should
not happen anyway, but let's try not to get completely confused if it does
(due to rewriter bugs or whatever).
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index fbbb5aeac96..9faf6b95e80 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -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. |