diff --git a/src/backend/lib/rbtree.c b/src/backend/lib/rbtree.c
index a9981dbadad..e1cc4110bd4 100644
--- a/src/backend/lib/rbtree.c
+++ b/src/backend/lib/rbtree.c
@@ -62,7 +62,7 @@ struct RBTree
 
 static RBTNode sentinel =
 {
-	RBTBLACK, RBTNIL, RBTNIL, NULL
+	.color = RBTBLACK,.left = RBTNIL,.right = RBTNIL,.parent = NULL
 };