diff --git a/src/backend/optimizer/util/tlist.c b/src/backend/optimizer/util/tlist.c
index aa2c2f8..c6ec785 100644
--- a/src/backend/optimizer/util/tlist.c
+++ b/src/backend/optimizer/util/tlist.c
@@ -553,15 +553,24 @@ make_pathtarget_from_tlist(List *tlist)
 	int			i;
 	ListCell   *lc;
 
-	target->sortgrouprefs = (Index *) palloc(list_length(tlist) * sizeof(Index));
-
 	i = 0;
 	foreach(lc, tlist)
 	{
 		TargetEntry *tle = (TargetEntry *) lfirst(lc);
 
 		target->exprs = lappend(target->exprs, tle->expr);
-		target->sortgrouprefs[i] = tle->ressortgroupref;
+
+		if (tle->ressortgroupref)
+		{
+			/*
+			 * We only allocate this array if there's a valid sortgroupref to
+			 * store.
+			 */
+			if (!target->sortgrouprefs)
+				target->sortgrouprefs = (Index *) palloc0(list_length(tlist) * sizeof(Index));
+
+			target->sortgrouprefs[i] = tle->ressortgroupref;
+		}
 		i++;
 	}