Fix a gradual memory leak in ExecReScanAgg(). Because the aggregation

hash table is allocated in a child context of the agg node's memory
context, MemoryContextReset() will reset but *not* delete the child
context. Since ExecReScanAgg() proceeds to build a new hash table
from scratch (in a new sub-context), this results in leaking the
header for the previous memory context. Therefore, use
MemoryContextResetAndDeleteChildren() instead.

Credit: My colleague Sailesh Krishnamurthy at Truviso for isolating
the cause of the leak.

diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index aa2517ca3ba430e5f66c9afc0aca630af93da22d..0d56f74a9cdc54c9f8d1f2ceeba029d2866149e0 100644 (file)
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -55,6 +55,7 @@
 #include "access/heapam.h"
 #include "catalog/pg_aggregate.h"
 #include "catalog/pg_operator.h"
+#include "catalog/pg_proc.h"
 #include "executor/executor.h"
 #include "executor/nodeAgg.h"
 #include "miscadmin.h"
@@ -603,6 +604,26 @@ build_hash_table(AggState *aggstate)
                                                                                          tmpmem);
 }
 
+/*
+ * Estimate per-hash-table-entry overhead for the planner.
+ *
+ * Note that the estimate does not include space for pass-by-reference
+ * transition data values.
+ */
+Size
+hash_agg_entry_size(int numAggs)
+{
+       Size            entrysize;
+
+       /* This must match build_hash_table */
+       entrysize = sizeof(AggHashEntryData) +
+               (numAggs - 1) *sizeof(AggStatePerGroupData);
+       /* Account for hashtable overhead */
+       entrysize += 2 * sizeof(void *);
+       entrysize = MAXALIGN(entrysize);
+       return entrysize;
+}
+
 /*
  * Find or create a hashtable entry for the tuple group containing the
  * given tuple.
@@ -1260,6 +1281,35 @@ ExecInitAgg(Agg *node, EState *estate)
                peraggstate->transfn_oid = transfn_oid = aggform->aggtransfn;
                peraggstate->finalfn_oid = finalfn_oid = aggform->aggfinalfn;
 
+               /* Check that aggregate owner has permission to call component fns */
+               {
+                       HeapTuple       procTuple;
+                       AclId           aggOwner;
+
+                       procTuple = SearchSysCache(PROCOID,
+                                                                          ObjectIdGetDatum(aggref->aggfnoid),
+                                                                          0, 0, 0);
+                       if (!HeapTupleIsValid(procTuple))
+                               elog(ERROR, "cache lookup failed for function %u",
+                                        aggref->aggfnoid);
+                       aggOwner = ((Form_pg_proc) GETSTRUCT(procTuple))->proowner;
+                       ReleaseSysCache(procTuple);
+
+                       aclresult = pg_proc_aclcheck(transfn_oid, aggOwner,
+                                                                                ACL_EXECUTE);
+                       if (aclresult != ACLCHECK_OK)
+                               aclcheck_error(aclresult, ACL_KIND_PROC,
+                                                          get_func_name(transfn_oid));
+                       if (OidIsValid(finalfn_oid))
+                       {
+                               aclresult = pg_proc_aclcheck(finalfn_oid, aggOwner,
+                                                                                        ACL_EXECUTE);
+                               if (aclresult != ACLCHECK_OK)
+                                       aclcheck_error(aclresult, ACL_KIND_PROC,
+                                                                  get_func_name(finalfn_oid));
+                       }
+               }
+
                /* resolve actual type of transition state, if polymorphic */
                aggtranstype = aggform->aggtranstype;
                if (aggtranstype == ANYARRAYOID || aggtranstype == ANYELEMENTOID)
@@ -1467,8 +1517,14 @@ ExecReScanAgg(AggState *node, ExprContext *exprCtxt)
        MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * node->numaggs);
        MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * node->numaggs);
 
-       /* Release all temp storage */
-       MemoryContextReset(node->aggcontext);
+       /*
+        * Release all temp storage. Note that with AGG_HASHED, the hash table
+        * is allocated in a sub-context of the aggcontext. We're going to
+        * rebuild the hash table from scratch, so we need to use
+        * MemoryContextResetAndDeleteChildren() to avoid leaking the old hash
+        * table's memory context header.
+        */
+       MemoryContextResetAndDeleteChildren(node->aggcontext);
 
        if (((Agg *) node->ss.ps.plan)->aggstrategy == AGG_HASHED)
        {