Hi Milan,

>
> I'm having troubles with deadlocks in very strange behaviour.
> ... There is a firebird.log entry
> that says database name and "deadlock" message, but application freeze.
> I have some lock print dumps (which Ann recommended me to make).

My ancient brain my be playing tricks on me, but it's telling me that at least
in olden days, a deadlock that showed up in the log was an internal deadlock,
in common terminology "a bug". I've forgotten which Firebird version you're
using but newer ones have fewer bugs than older, so upgrading might help.
You might try looking at the lock prints - Helen's book has a chapter on
understanding lock prints. What you want to find is a cycle in the wait
list between lock requests.

Good luck,

Ann