3 files changed, 66 insertions, 29 deletions

diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index c63758cb2b7..16e5537f7f9 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -2181,22 +2181,14 @@ fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
 	if (IsA(node, Aggref))
 	{
 		Aggref	   *aggref = (Aggref *) node;
+		Param	   *aggparam;
 
 		/* See if the Aggref should be replaced by a Param */
-		if (context->root->minmax_aggs != NIL &&
-			list_length(aggref->args) == 1)
+		aggparam = find_minmax_agg_replacement_param(context->root, aggref);
+		if (aggparam != NULL)
 		{
-			TargetEntry *curTarget = (TargetEntry *) linitial(aggref->args);
-			ListCell   *lc;
-
-			foreach(lc, context->root->minmax_aggs)
-			{
-				MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
-
-				if (mminfo->aggfnoid == aggref->aggfnoid &&
-					equal(mminfo->target, curTarget->expr))
-					return (Node *) copyObject(mminfo->param);
-			}
+			/* Make a copy of the Param for paranoia's sake */
+			return (Node *) copyObject(aggparam);
 		}
 		/* If no match, just fall through to process it normally */
 	}
@@ -3225,22 +3217,14 @@ fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
 	if (IsA(node, Aggref))
 	{
 		Aggref	   *aggref = (Aggref *) node;
+		Param	   *aggparam;
 
 		/* See if the Aggref should be replaced by a Param */
-		if (context->root->minmax_aggs != NIL &&
-			list_length(aggref->args) == 1)
+		aggparam = find_minmax_agg_replacement_param(context->root, aggref);
+		if (aggparam != NULL)
 		{
-			TargetEntry *curTarget = (TargetEntry *) linitial(aggref->args);
-			ListCell   *lc;
-
-			foreach(lc, context->root->minmax_aggs)
-			{
-				MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
-
-				if (mminfo->aggfnoid == aggref->aggfnoid &&
-					equal(mminfo->target, curTarget->expr))
-					return (Node *) copyObject(mminfo->param);
-			}
+			/* Make a copy of the Param for paranoia's sake */
+			return (Node *) copyObject(aggparam);
 		}
 		/* If no match, just fall through to process it normally */
 	}
@@ -3395,6 +3379,38 @@ set_windowagg_runcondition_references(PlannerInfo *root,
 	return newlist;
 }
 
+/*
+ * find_minmax_agg_replacement_param
+ *		If the given Aggref is one that we are optimizing into a subquery
+ *		(cf. planagg.c), then return the Param that should replace it.
+ *		Else return NULL.
+ *
+ * This is exported so that SS_finalize_plan can use it before setrefs.c runs.
+ * Note that it will not find anything until we have built a Plan from a
+ * MinMaxAggPath, as root->minmax_aggs will never be filled otherwise.
+ */
+Param *
+find_minmax_agg_replacement_param(PlannerInfo *root, Aggref *aggref)
+{
+	if (root->minmax_aggs != NIL &&
+		list_length(aggref->args) == 1)
+	{
+		TargetEntry *curTarget = (TargetEntry *) linitial(aggref->args);
+		ListCell   *lc;
+
+		foreach(lc, root->minmax_aggs)
+		{
+			MinMaxAggInfo *mminfo = (MinMaxAggInfo *) lfirst(lc);
+
+			if (mminfo->aggfnoid == aggref->aggfnoid &&
+				equal(mminfo->target, curTarget->expr))
+				return mminfo->param;
+		}
+	}
+	return NULL;
+}
+
+
 /*****************************************************************************
  *					QUERY DEPENDENCY MANAGEMENT
  *****************************************************************************/
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index da2d8abe015..250ba8edcb8 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -2835,8 +2835,8 @@ finalize_plan(PlannerInfo *root, Plan *plan,
 }
 
 /*
- * finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
- * expression tree to the result set.
+ * finalize_primnode: add IDs of all PARAM_EXEC params that appear (or will
+ * appear) in the given expression tree to the result set.
  */
 static bool
 finalize_primnode(Node *node, finalize_primnode_context *context)
@@ -2853,7 +2853,26 @@ finalize_primnode(Node *node, finalize_primnode_context *context)
 		}
 		return false;			/* no more to do here */
 	}
-	if (IsA(node, SubPlan))
+	else if (IsA(node, Aggref))
+	{
+		/*
+		 * Check to see if the aggregate will be replaced by a Param
+		 * referencing a subquery output during setrefs.c.  If so, we must
+		 * account for that Param here.  (For various reasons, it's not
+		 * convenient to perform that substitution earlier than setrefs.c, nor
+		 * to perform this processing after setrefs.c.  Thus we need a wart
+		 * here.)
+		 */
+		Aggref	   *aggref = (Aggref *) node;
+		Param	   *aggparam;
+
+		aggparam = find_minmax_agg_replacement_param(context->root, aggref);
+		if (aggparam != NULL)
+			context->paramids = bms_add_member(context->paramids,
+											   aggparam->paramid);
+		/* Fall through to examine the agg's arguments */
+	}
+	else if (IsA(node, SubPlan))
 	{
 		SubPlan    *subplan = (SubPlan *) node;
 		Plan	   *plan = planner_subplan_get_plan(context->root, subplan);
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 5fc900737d8..31c188176b7 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -110,6 +110,8 @@ extern bool innerrel_is_unique(PlannerInfo *root,
  */
 extern Plan *set_plan_references(PlannerInfo *root, Plan *plan);
 extern bool trivial_subqueryscan(SubqueryScan *plan);
+extern Param *find_minmax_agg_replacement_param(PlannerInfo *root,
+												Aggref *aggref);
 extern void record_plan_function_dependency(PlannerInfo *root, Oid funcid);
 extern void record_plan_type_dependency(PlannerInfo *root, Oid typid);
 extern bool extract_query_dependencies_walker(Node *node, PlannerInfo *context);