dba_delete() problems

Hello all, I've got a bit of a problem at the moment. I'm using the dba_ functions to do some simple database access, and I have the need to delete some items from the database from time to time. When dba_delete() is called, it returns true, indicating that the key/value pair was deleted. After making the deletions, dba_sync() is called. The problem is, the database size never decreases no matter how much you delete (even if you remove every item). On examination of the .dbm files in text editor, I found that all the data from every key/value pair was still there, and hadn't been removed as I wanted it to. This is extremely bad for the database, because it grows constantly with no way to decrease the size other than flat out deleting it, which I don't want to do. Am I doing something wrong with deleting the keys, or is this an issue with dba? Notes: I'm using Apache 1.3.24 and PHP 4.2.1 on Windows XP Professional. The database is accessed using the db3 handler. Thank you in advance for any replies, Steve