Suppose I have a zclass which inherits like this my_ZClass( my_python_class( Persistence.Persistent,Acquisition.Implicit)) In my_python_class, I have something like the following segment: def doStuffToCount(self, newcount): _count=self._count # get persistent count _count=_count+newcount # increase count ... # maybe do other stuff self._count=_count # save persistent count again return _count My reading of Michel P. and Jim F.'s posts in recent threads about Persistence and ZODB3, is that this this method above is basically an atomic opertation as far as ODB3 is concerned, and I do not have to worry that another thread is going to touch self._count in between _count=self._count and self._count=_count. Is this correct? If I am misunderstanding, is there the equivalent to java's synchronized keyword that one would use in this scenario? Thanks, -- Alex Rice | alrice@swcp.com | http://www.swcp.com/~alrice Current Location: N. Rio Grande Bioregion, Southwestern USA