The following bug has been logged online:
Bug reference: 5039
Logged by: Kamil Roman
Email address: kamil(dot)lech(dot)roman(at)gmail(dot)com
PostgreSQL version: 8.3.7
Operating system: Windows XP
Description: 'i' flag i in regexp_replace ignored for polish letters
Details:
select regexp_replace('LUBŻKOĄŚĆĘŁŃÓ','[ośżźćęąłńó]',
'_','ig');
returns 'LUBŻK_ĄŚĆĘŁŃÓ' and it should return LUB_K_______