[Zope] Generating unique keys

[Michel Pelletier]

Stuart 'Zen' Bishop wrote:

> > Have you seen my How-To on generating Unique ids?
> > It may not be _exactly_ what you are looking for, but it will provide a
> > decent starting place.

> But What happens when two ID's are generated at exactly the same time through
> different threads?

ZODB will not allow two persistent objects to be overwriten at the same
time.

> So an object can simply have an integer counter that is incremented
> as necessary, and if two threads try to modify the counter at about the same
> time, the one that tries to commit last will rollback and be reexecuted.
> If this is true, its so trivial a counter class and locking is totally
> unnecessary :-) And it should work with ZEO as well from what I understand
> of its architecture.

Yep.  Because it's persistent however, every unique id will cause a
transaction, in a ZEO environment, this would cause lots of object
colisions over the wire.  Probably not very scalable.

ZODB has a lot of potention for non version-based storages however, we
are currently working on an projecy oriented toward just that.

-Michel