text: DROP EXTENSION IF EXISTS www_fdw CASCADE;
  CREATE EXTENSION www_fdw;
  CREATE SERVER www_fdw_server_test FOREIGN DATA WRAPPER www_fdw OPTIONS (uri 'http://localhost:7777', request_serialize_callback 'test_request_serialize_callback');
  CREATE USER MAPPING FOR current_user SERVER www_fdw_server_test;
  CREATE FOREIGN TABLE www_fdw_test (
  	title text,                                                        
  	link text,
  	snippet text
  ) SERVER www_fdw_server_test;
  CREATE OR REPLACE FUNCTION test_request_serialize_callback(options WWWFdwOptions, quals text, INOUT url text, INOUT post WWWFdwPostParameters) AS $$
  BEGIN
  	RAISE DEBUG 'options parameter: %', options;
  	RAISE DEBUG 'quals parameter: %', quals;
  	RAISE DEBUG 'url parameter: %', url;
  	RAISE DEBUG 'post parameter: %', post;
  	url := url || '?title=titel';
  END; $$ LANGUAGE PLPGSQL;