[robert] > ... > PS: how does ZODB work with this kind of problem? I thought is uses cPickle?
It does. Each thread in a ZODB application typically uses its own connection to a database. As a result, each thread gets its own consistent view of database objects, which can (and routinely does) vary across threads. No app-level synchronization is necessary because no sharing of in-memory objects occurs. When N threads each load a single persistent object from its own connection, N distinct in-memory revisions of that object are created (one per connection == one per thread). If more than one thread modifies the same persistent object, the first thread to commit its changes "wins", and later threads that try to commit changes to the same object may suffer a ConflictError exception at commit time. Between transaction boundaries, each thread has an independent view of database state. Pragmatically, it's much more like programming with multiple processes than with multiple threads. -- http://mail.python.org/mailman/listinfo/python-list
