[Zope] ConflictError (ID-Counter for all Documents)

I am developing a simple Document Management System with a python product. All documents are in one folder. If a new document gets created I do the following: root.last_id=root.last_id+1 If I stress test this with httperf I get ConflictErrors. I searched and found two solutions: Catch the Exception, and retry it. Use PCounter from ZODB/test/ConflictResolution.py Are there other, better solutions? Which one is better? thomas