5 files changed, 56 insertions, 6 deletions

diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 2bf48c54e3c..4c82176671b 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -2666,11 +2666,13 @@ ExecReScanAgg(AggState *node)
 			return;
 
 		/*
-		 * If we do have the hash table and the subplan does not have any
-		 * parameter changes, then we can just rescan the existing hash table;
-		 * no need to build it again.
+		 * If we do have the hash table, and the subplan does not have any
+		 * parameter changes, and none of our own parameter changes affect
+		 * input expressions of the aggregated functions, then we can just
+		 * rescan the existing hash table; no need to build it again.
 		 */
-		if (outerPlan->chgParam == NULL)
+		if (outerPlan->chgParam == NULL &&
+			!bms_overlap(node->ss.ps.chgParam, aggnode->aggParams))
 		{
 			ResetTupleHashIterator(node->hashtable, &node->hashiter);
 			return;
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 3f19226b06a..db492a7dd1d 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -846,6 +846,7 @@ _copyAgg(const Agg *from)
 		COPY_POINTER_FIELD(grpOperators, from->numCols * sizeof(Oid));
 	}
 	COPY_SCALAR_FIELD(numGroups);
+	COPY_BITMAPSET_FIELD(aggParams);
 	COPY_NODE_FIELD(groupingSets);
 	COPY_NODE_FIELD(chain);
 
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 2487f396cce..5c03e9f2aa8 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -683,7 +683,7 @@ _outAgg(StringInfo str, const Agg *node)
 		appendStringInfo(str, " %u", node->grpOperators[i]);
 
 	WRITE_LONG_FIELD(numGroups);
-
+	WRITE_BITMAPSET_FIELD(aggParams);
 	WRITE_NODE_FIELD(groupingSets);
 	WRITE_NODE_FIELD(chain);
 }
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 40f801e41c8..6af68b08d27 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -4535,6 +4535,7 @@ make_agg(PlannerInfo *root, List *tlist, List *qual,
 	node->grpColIdx = grpColIdx;
 	node->grpOperators = grpOperators;
 	node->numGroups = numGroups;
+	node->aggParams = NULL;		/* SS_finalize_plan() will fill this */
 
 	copy_plan_costsize(plan, lefttree); /* only care about copying size */
 	cost_agg(&agg_path, root,
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 979802f70d5..e400ea983cc 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -81,6 +81,7 @@ static Bitmapset *finalize_plan(PlannerInfo *root,
 			  Bitmapset *valid_params,
 			  Bitmapset *scan_params);
 static bool finalize_primnode(Node *node, finalize_primnode_context *context);
+static bool finalize_agg_primnode(Node *node, finalize_primnode_context *context);
 
 
 /*
@@ -2558,6 +2559,29 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params,
 										 locally_added_param);
 			break;
 
+		case T_Agg:
+			{
+				Agg		   *agg = (Agg *) plan;
+
+				/*
+				 * AGG_HASHED plans need to know which Params are referenced
+				 * in aggregate calls.  Do a separate scan to identify them.
+				 */
+				if (agg->aggstrategy == AGG_HASHED)
+				{
+					finalize_primnode_context aggcontext;
+
+					aggcontext.root = root;
+					aggcontext.paramids = NULL;
+					finalize_agg_primnode((Node *) agg->plan.targetlist,
+										  &aggcontext);
+					finalize_agg_primnode((Node *) agg->plan.qual,
+										  &aggcontext);
+					agg->aggParams = aggcontext.paramids;
+				}
+			}
+			break;
+
 		case T_WindowAgg:
 			finalize_primnode(((WindowAgg *) plan)->startOffset,
 							  &context);
@@ -2566,7 +2590,6 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params,
 			break;
 
 		case T_Hash:
-		case T_Agg:
 		case T_Material:
 		case T_Sort:
 		case T_Unique:
@@ -2711,6 +2734,29 @@ finalize_primnode(Node *node, finalize_primnode_context *context)
 }
 
 /*
+ * finalize_agg_primnode: find all Aggref nodes in the given expression tree,
+ * and add IDs of all PARAM_EXEC params appearing within their aggregated
+ * arguments to the result set.
+ */
+static bool
+finalize_agg_primnode(Node *node, finalize_primnode_context *context)
+{
+	if (node == NULL)
+		return false;
+	if (IsA(node, Aggref))
+	{
+		Aggref	   *agg = (Aggref *) node;
+
+		/* we should not consider the direct arguments, if any */
+		finalize_primnode((Node *) agg->args, context);
+		finalize_primnode((Node *) agg->aggfilter, context);
+		return false;			/* there can't be any Aggrefs below here */
+	}
+	return expression_tree_walker(node, finalize_agg_primnode,
+								  (void *) context);
+}
+
+/*
  * SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
  *
  * The plan is expected to return a scalar value of the given type/collation.