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authorTom Lane <tgl@sss.pgh.pa.us>2006-12-26 21:37:20 +0000
committerTom Lane <tgl@sss.pgh.pa.us>2006-12-26 21:37:20 +0000
commit0cbc5b1ed49ed744e856687b1d5e36d312327a34 (patch)
tree6a56142c89f023731a991141114ef070c5a3f470 /src/backend/executor/execMain.c
parent68996463d405a0e3e35f81371ffebbbaff7c1f63 (diff)
downloadpostgresql-0cbc5b1ed49ed744e856687b1d5e36d312327a34.tar.gz
postgresql-0cbc5b1ed49ed744e856687b1d5e36d312327a34.zip
Fix failure due to accessing an already-freed tuple descriptor in a plan
involving HashAggregate over SubqueryScan (this is the known case, there may well be more). The bug is only latent in releases before 8.2 since they didn't try to access tupletable slots' descriptors during ExecDropTupleTable. The least bogus fix seems to be to make subqueries share the parent query's memory context, so that tupdescs they create will have the same lifespan as those of the parent query. There are comments in the code envisioning going even further by not having a separate child EState at all, but that will require rethinking executor access to range tables, which I don't want to tackle right now. Per bug report from Jean-Pierre Pelletier.
Diffstat (limited to 'src/backend/executor/execMain.c')
-rw-r--r--src/backend/executor/execMain.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 6db354cd4f9..ec7959a9f5f 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -26,7 +26,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.281 2006/12/04 02:06:55 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.282 2006/12/26 21:37:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2247,6 +2247,10 @@ EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
rtsize = list_length(estate->es_range_table);
+ /*
+ * It's tempting to think about using CreateSubExecutorState here, but
+ * at present we can't because of memory leakage concerns ...
+ */
epq->estate = epqstate = CreateExecutorState();
oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);