Apart from the DBI's tracing you might want to see if your database allows some tracing. Eg. if you were using MS SQL Server you might what to try the "SQL Profiler" that gets installed with it. It may give you more information than you need.

Jenda
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
   -- Rick Osborne

Edit by castaway: Closed small tag in signature