[jboss-user] [jBPM Users] - Re: Hibernate, Sessions, and Sync - Oh my!

[MohReece]

Michael, it looks like you're doing some custom asynchronous continuation, and the moment in which the new transaction is started (i.e. the jBPM context created) isn't related at all of the old transaction, which in a sense 'spawned' it - am I reading that correctly?

We have been doing something similar in our system (we're still using 3.1.4 for now, I guess you have a similar predicament in which upgrading an existing system just is easier said than done), and we encountered the same inconsistent and unpredictable SOSE occurrences.

The problem was that we used an indeterministic strategy for creating a new jBPM context in a new thread - we didn't wait for the old one to be closed and were 'hoping for the best' - unknowingly at first, of course.

We found a solution by making sure the new transaction is started only after the old one has ended: digging a little beyond the jBPM API into the Hibernate API, in which the org.hibernate.Transaction interface has the possibility to register a callback object (which must implement the javax.transaction.Synchronization interface). The latter object then is called before and after the two-phase-commit, and we used this last call as a starting point for the new transaction.

>From within an opened transaction we use something like this:

  | jbpmContext.getSession().getTransaction().registerSynchronization(new Synchronization() {
  | 	public void beforeCompletion() {
  | 		// We're not using this one ourselves...
  | 	}
  | 
  | 	public void afterCompletion(int status) {
  | 		// Here we spawn a new thread which can safely open its own jBPM context...
  | 	}
  | });
  | 

Hope this helps you out a little bit!

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