diff --git a/src/backend/utils/resource_manager/memquota.c b/src/backend/utils/resource_manager/memquota.c
index d2b01c36f38156891f211112d26326088a48229a..5c6885632419fef37038a66473fa602520e7ec85 100644
--- a/src/backend/utils/resource_manager/memquota.c
+++ b/src/backend/utils/resource_manager/memquota.c
@@ -1035,6 +1035,10 @@ ResourceManagerGetQueryMemoryLimit(PlannedStmt* stmt)
 	if (Gp_role != GP_ROLE_DISPATCH)
 		return 0;
 
+	/* no limits in single user mode. */
+	if (!IsUnderPostmaster)
+		return 0;
+
 	Assert(gp_session_id > -1);
 	Assert(ActivePortal != NULL);