BEGIN;
DROP TABLE  IF EXISTS test;
DROP SEQUENCE IF EXISTS  test_seq;
--SET client_min_messages = 'notice';

CREATE TABLE test (
  id INTEGER, 
  status INTEGER, 
  value numeric
);

CREATE SEQUENCE test_seq;

CREATE OR REPLACE FUNCTION test_tr() RETURNS trigger AS $body$
DECLARE
	seq integer;
BEGIN
	seq := nextval('test_seq');
	RAISE NOTICE 'Started: %', seq;
	RAISE NOTICE 'SO: %,  OLD: %', seq, OLD;
	IF new.status != old.status THEN		
		UPDATE test SET value = 3 WHERE id = new.id;
	END IF;
	RAISE NOTICE ' % , %' , seq, (SELECT (test.*)::text FROM test WHERE id = new.id);
	RAISE NOTICE 'FN: %, RETURNED NEW: %', seq, new;
	RETURN new;
END
$body$ LANGUAGE 'plpgsql';

CREATE TRIGGER test_tr BEFORE UPDATE ON test FOR EACH ROW EXECUTE PROCEDURE test_tr();

INSERT INTO test (id, status, value) VALUES (1, 1, 1);

UPDATE test SET status = 2, value = 2 WHERE id = 1;

SELECT * FROM test;

ROLLBACK;
---------------------------------
NOTICE:  Started: 1
NOTICE:  SO: 1,  OLD: (1,1,1)
NOTICE:  Started: 2
CONTEXT:  SQL statement "UPDATE test SET value = 3 WHERE id = new.id"
PL/pgSQL function "test_tr" line 9 at SQL statement
NOTICE:  SO: 2,  OLD: (1,1,1)
CONTEXT:  SQL statement "UPDATE test SET value = 3 WHERE id = new.id"
PL/pgSQL function "test_tr" line 9 at SQL statement
NOTICE:   2 , (1,1,1)
CONTEXT:  SQL statement "UPDATE test SET value = 3 WHERE id = new.id"
PL/pgSQL function "test_tr" line 9 at SQL statement
NOTICE:  FN: 2, RETURNED NEW: (1,1,3)
CONTEXT:  SQL statement "UPDATE test SET value = 3 WHERE id = new.id"
PL/pgSQL function "test_tr" line 9 at SQL statement
NOTICE:   1 , (1,1,3)
NOTICE:  FN: 1, RETURNED NEW: (1,2,2)