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authorTom Lane <tgl@sss.pgh.pa.us>2020-11-03 16:16:36 -0500
committerTom Lane <tgl@sss.pgh.pa.us>2020-11-03 16:16:36 -0500
commit55416b26a98fcf354af88cdd27fc2e045453b68a (patch)
tree5193d4c50ef6caa4a472cc274238f049c53e1b81
parent136f87ea57b3a7a6bf64c832a5e1b69e18091775 (diff)
downloadpostgresql-55416b26a98fcf354af88cdd27fc2e045453b68a.tar.gz
postgresql-55416b26a98fcf354af88cdd27fc2e045453b68a.zip
Guard against core dump from uninitialized subplan.
If the planner erroneously puts a non-parallel-safe SubPlan into a parallelized portion of the query tree, nodeSubplan.c will fail in the worker processes because it finds a null in es_subplanstates, which it's unable to cope with. It seems worth a test-and-elog to make that an error case rather than a core dump case. This probably should have been included in commit 16ebab688, which was responsible for allowing nulls to appear in es_subplanstates to begin with. So, back-patch to v10 where that came in. Discussion: https://postgr.es/m/924226.1604422326@sss.pgh.pa.us
-rw-r--r--src/backend/executor/nodeSubplan.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 5e9ce229b89..62ef1385710 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -798,7 +798,15 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
sstate->planstate = (PlanState *) list_nth(estate->es_subplanstates,
subplan->plan_id - 1);
- /* ... and to its parent's state */
+ /*
+ * This check can fail if the planner mistakenly puts a parallel-unsafe
+ * subplan into a parallelized subquery; see ExecSerializePlan.
+ */
+ if (sstate->planstate == NULL)
+ elog(ERROR, "subplan \"%s\" was not initialized",
+ subplan->plan_name);
+
+ /* Link to parent's state, too */
sstate->parent = parent;
/* Initialize subexpressions */