What does PostCommitListeners are too slow imply? How is it fixed?

Question

I get the following error when several event handlers are called in succesion:

See post: Firing even handlers when structured templates are used to create document? for background

here is the error log.

2012-04-06 13:27:57,152 WARN  [org.nuxeo.ecm.core.event.tx.PostCommitSynchronousRunner] PostCommitListeners are too slow, check debug log ...
2012-04-06 13:27:57,153 WARN  [org.nuxeo.ecm.core.event.tx.PostCommitSynchronousRunner] Exit before the end of processing

bruce_Grant · Accepted Answer

PostCommitSynchronousRunner creates a new synchronous thread to run the listener process. The code has a default timeout of 300ms for the synchronous event. If the synchronous thread is still alive after 300ms then the error message that you see above is thrown.

So if you are creating a document in the listener then I might start with the database log and see how long the database transactions are taking as this is typically the slowest part of a transaction.