(note that I'm replying to my own message, because I somehow managed to
delete your message this morning)

> I'm not using Jaybird Pooling but built my own simple based on
> BlockingQueue.

In my experience building a connection pool to function correctly is
hard, that is one of the reasons I have deprecated the
org.firebirdsql.pool package in Jaybird 2.2 and removed it in 3.0.

> The damn DataExpress library make a lot of stuff behind the scenes
> that is out of the control. By inspecting the Database class source
> code I found that by default it creates transactions which does not
> cope well with Jaybird when called from several threads. I disabled
> the transaction on the Database object and the problem went away.

You should avoid having the same connection used from multiple threads
at the same time. At least, it sounds like that is what is happening
right now, and if you can't avoid doing that, it would be better to
upgrade to 2.2.11 because of JDBC-435
(http://tracker.firebirdsql.org/browse/JDBC-435).

> In time we will update to later version of Jaybird and migrate away
> from DataExpress. The problem is that we have several hundreds of
> installations.

Mark
--
Mark Rotteveel