Created attachment 570370 [details] Stack trace I have created a test which runs multiple threads in parallel. Each thread has its own ksession. Every thread uses its own EntityManager. Threads share the same database for persisting process instances, work items and session information. If I use single entity manager which is shared by the threads, then everything is persisted fine. I have attached error stack trace in file, because the stack trace is very long. This stack trace happened with MySQL database. I have also tried local HSQL database, but the exception is a bit different and shorter. I am working on a test case, it is available here https://github.com/jsvitak/jbpm/blob/parallelProcessPersistence/jbpm-test/src/test/java/org/jbpm/persistence/ProcessMultiThreadPersistenceTest.java But it is not finished and working yet. I am working on a pull request.
Jiri, It seems like this might be a duplicate of 805899. If this is not a duplicate, could you add some additional detail as to why the issue/cause here is different than in 805899? Thanks, Marco
It turns out that 805899 covers this same issue, please see that issue for more information. *** This bug has been marked as a duplicate of bug 805899 ***