diff --git a/src/backend/utils/ag_guc.c b/src/backend/utils/ag_guc.c
index d9a99f66e..86b4e00bc 100644
--- a/src/backend/utils/ag_guc.c
+++ b/src/backend/utils/ag_guc.c
@@ -42,4 +42,5 @@ void define_config_params(void)
                              NULL,
                              NULL,
                              NULL);
+    EmitWarningsOnPlaceholders("age");
 }