diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 9941dfe65e..ddb277cdf0 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -2113,12 +2113,22 @@ create_agg_plan(PlannerInfo *root, AggPath *best_path)
 	Plan	   *subplan;
 	List	   *tlist;
 	List	   *quals;
+	int			flags;
 
 	/*
 	 * Agg can project, so no need to be terribly picky about child tlist, but
-	 * we do need grouping columns to be available
+	 * we do need grouping columns to be available. We are a bit more careful
+	 * with hash aggregate, where we explicitly request small tlist to minimize
+	 * I/O needed for spilling (possibly not known already).
 	 */
-	subplan = create_plan_recurse(root, best_path->subpath, CP_LABEL_TLIST);
+	flags = CP_LABEL_TLIST;
+
+	/* ensure small tlist for hash aggregate */
+	if (best_path->aggstrategy == AGG_HASHED ||
+		best_path->aggstrategy == AGG_MIXED)
+		flags |= CP_SMALL_TLIST;
+
+	subplan = create_plan_recurse(root, best_path->subpath, flags);
 
 	tlist = build_path_tlist(root, &best_path->path);
 
@@ -2209,7 +2219,8 @@ create_groupingsets_plan(PlannerInfo *root, GroupingSetsPath *best_path)
 	 * Agg can project, so no need to be terribly picky about child tlist, but
 	 * we do need grouping columns to be available
 	 */
-	subplan = create_plan_recurse(root, best_path->subpath, CP_LABEL_TLIST);
+	subplan = create_plan_recurse(root, best_path->subpath,
+								  CP_LABEL_TLIST | CP_SMALL_TLIST);
 
 	/*
 	 * Compute the mapping from tleSortGroupRef to column index in the child's