There is no doubt that simple deletions via Hibernate takes too much time.

I think there must have been a gate in hibernate to jdbc, that doesnt consider about rules and available to use when you need "only" simple SQL to execute

such as

session.execute("Delete from CAT where type = 1");

Now I need to delete for about 20000 records, for consistency I used hibernate in all my db work, I had to write

session.delete("Select from.....")

it took for about 15 minutes, where as if I had been able to write a delete SQL, it should take at most 1 minute to clear these entries from db.

noone ever claimed differently.

Have you tried using hibernate 3.1 which has bulk update/delete HQL support ? Or simply just use sql for large bulk deletes ? (use the right tool for the right job)