Are you sure the cause is JDBCOptimisticLock?
If you use the default container configuration, do you see the same exception?
If I use the default QueuedPessimisticEJBLock I do not get the same error.
I do have a request per second or more to a Finder Method and if I use the QueuedPessimisticEJBLock all my request are serialized :)
I am using reentrant="false"
If it works stably with pessimistic lock, then it's a bug in optimistic lock. It would be great, if you could provide a testcase and submit a bug report.
Thank you very much.