--- In firebird-support@yahoogroups.com, Christian Kaufmann
...

> I think, it's not a PHP problem but a problem of my configuration of my
> Firebird server.
>
> I really like Firebird, but to find solutions to such problems here is
> rather difficult for me. It's more "fishing in the dark" right now.
>
> All I know, that in general my application / database runs fine, but at
> some points, repsonse times to request are just too long. And here I'm
> stuck, I don't have a good plan to identify the real problem and to
> solve it.

Look at database statistics at time when response times is big and find out if auto-sweep is the reason.

As you already use FB 2.5 - try its new trace feature and log all long-running queries to analyze them.

Regards,
Vlad