>To me this sounds like the cooperative garbage collection kicks in when you select from the table. You may want to consider dropping the table entirely and recreating it. Alternatively, switch to SuperServer and set its garbage collection policy to background (I believe this was introduced in Firebird 2.0 or 2.1, so won't help with Firebird 1.5).
Thanks Mark. I have actually done a complete drop on the table once, but it has 27 stored procedures that are dependent on it, so they all have to be dropped too. I did write a Linux script to do that, but after I had done it I had read that this might not make any difference to the garbage collection unless I do a backup & restore of it afterwards. Does that make sense to you? Myles