WIP: Add CDB_Federated_Server_Unregister

scripts-available/CDB_ForeignTable.sql

@@ -184,15 +184,17 @@ RETURNS void AS $$
 DECLARE
   row record;
   option record;
-  fdw_objects_name NAME := @extschema@.__CDB_User_FDW_Object_Names(fdw_input_name);
+  fdw_objects_name NAME := fdw_input_name;
 BEGIN
   -- TODO: refactor with original function
   -- This function tries to be as idempotent as possible, by not creating anything more than once
   -- (not even using IF NOT EXIST to avoid throwing warnings)
   IF NOT EXISTS ( SELECT * FROM pg_extension WHERE extname = 'postgres_fdw') THEN
     CREATE EXTENSION postgres_fdw;
-    RAISE NOTICE 'Created postgres_fdw EXTENSION';
+    RAISE EXCEPTION 'postgres_fdw extension is not installed'
+        USING HINT = 'Please install it with "CREATE EXTENSION postgres_fdw"';
   END IF;
+
   -- Create FDW first if it does not exist
   IF NOT EXISTS ( SELECT * FROM pg_foreign_server WHERE srvname = fdw_objects_name)
     THEN