diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 6da0dcd61c..763e348d52 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -3182,6 +3182,15 @@ standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels)
  * volatile qual could succeed for some SRF output rows and fail for others,
  * a behavior that cannot occur if it's evaluated before SRF expansion.
  *
+ * 6. If the subquery has nonempty grouping sets, we cannot push down any
+ * quals.  The concern here is that a qual referencing a "constant" grouping
+ * column could get constant-folded, which would be improper because the value
+ * is potentially nullable by grouping-set expansion.  This restriction could
+ * be removed if we had a parsetree representation that shows that such
+ * grouping columns are not really constant.  (There are other ideas that
+ * could be used to relax this restriction, but that's the approach most
+ * likely to get taken in the future.)
+ *
  * In addition, we make several checks on the subquery's output columns to see
  * if it is safe to reference them in pushed-down quals.  If output column k
  * is found to be unsafe to reference, we set safetyInfo->unsafeColumns[k]
@@ -3226,6 +3235,10 @@ subquery_is_pushdown_safe(Query *subquery, Query *topquery,
 	if (subquery->limitOffset != NULL || subquery->limitCount != NULL)
 		return false;
 
+	/* Check point 6 */
+	if (subquery->groupClause && subquery->groupingSets)
+		return false;
+
 	/* Check points 3, 4, and 5 */
 	if (subquery->distinctClause ||
 		subquery->hasWindowFuncs ||