From 248f1ac813e7a5fd83816b1d85a3d4a14e7574a2 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 21 Jun 2012 17:26:31 -0400 Subject: [PATCH] Fix memory leak in ARRAY(SELECT ...) subqueries. Repeated execution of an uncorrelated ARRAY_SUBLINK sub-select (which I think can only happen if the sub-select is embedded in a larger, correlated subquery) would leak memory for the duration of the query, due to not reclaiming the array generated in the previous execution. Per bug #6698 from Armando Miraglia. Diagnosis and fix idea by Heikki, patch itself by me. This has been like this all along, so back-patch to all supported versions. --- src/backend/executor/nodeSubplan.c | 18 +++++++++++++----- src/include/nodes/execnodes.h | 1 + 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c index d03416a56b..e69eb5c6ed 100644 --- a/src/backend/executor/nodeSubplan.c +++ b/src/backend/executor/nodeSubplan.c @@ -668,6 +668,7 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent) * initialize my state */ sstate->curTuple = NULL; + sstate->curArray = PointerGetDatum(NULL); sstate->projLeft = NULL; sstate->projRight = NULL; sstate->hashtable = NULL; @@ -1004,16 +1005,23 @@ ExecSetParamPlan(SubPlanState *node, ExprContext *econtext) int paramid = linitial_int(subplan->setParam); ParamExecData *prm = &(econtext->ecxt_param_exec_vals[paramid]); - prm->execPlan = NULL; - /* We build the result in query context so it won't disappear */ + /* + * We build the result array in query context so it won't disappear; + * to avoid leaking memory across repeated calls, we have to remember + * the latest value, much as for curTuple above. + */ + if (node->curArray != PointerGetDatum(NULL)) + pfree(DatumGetPointer(node->curArray)); if (astate != NULL) - prm->value = makeArrayResult(astate, - econtext->ecxt_per_query_memory); + node->curArray = makeArrayResult(astate, + econtext->ecxt_per_query_memory); else { MemoryContextSwitchTo(econtext->ecxt_per_query_memory); - prm->value = PointerGetDatum(construct_empty_array(subplan->firstColType)); + node->curArray = PointerGetDatum(construct_empty_array(subplan->firstColType)); } + prm->execPlan = NULL; + prm->value = node->curArray; prm->isnull = false; } else if (!found) diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index 23a86e9084..5348fa892d 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -663,6 +663,7 @@ typedef struct SubPlanState ExprState *testexpr; /* state of combining expression */ List *args; /* states of argument expression(s) */ HeapTuple curTuple; /* copy of most recent tuple from subplan */ + Datum curArray; /* most recent array from ARRAY() subplan */ /* these are used when hashing the subselect's output: */ ProjectionInfo *projLeft; /* for projecting lefthand exprs */ ProjectionInfo *projRight; /* for projecting subselect output */