PostgreSQL在函数内返回returning

开发咨询，想在function返回之前insert或者update的值，postgresql有个returning的特性，可以返回之前各种DML(insert,delete,update)掉的值，比mysql的返回last_insert_id更丰富一点。

环境：
PostgreSQL 9.3.2
CentOS 6.3

类似的Function如下：

CREATE OR REPLACE FUNCTION fun_test(v_id int, v_remark text)
  RETURNS integer AS
$BODY$

declare 
   o_id int;
begin

   perform 1  from foo where id=v_id and remark = v_remark ;

if not found then 
   insert into foo(remark) values (v_remark) returning id into o_id;
return  o_id;
else 
   update foo set  id=v_id, remark=v_remark where id=v_id and remark = v_remark  returning id into o_id;
return o_id ;
end if;

exception when others then
raise exception 'exec fun fun_test error,PLZ contact DBA！';
return  999;

end;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION fun_test(int, text)
  OWNER TO postgres;

参考：
http://my.oschina.net/Kenyon/blog/54376
http://my.oschina.net/Kenyon/blog/108303