Of course UUID is not guaranteed to be absolutely random. But it is suspicious these similarities happen is a small timeframe, so I think that the image got restarted a few times, but generated the same ID.
Uko > On 6 Feb 2017, at 14:35, Sven Van Caekenberghe <[email protected]> wrote: > > >> On 6 Feb 2017, at 14:17, Yuriy Tymchuk <[email protected]> wrote: >> >> Hi everyone, >> >> I’m using the session id (Smalltalk session id) for my data recording, so I >> can distinguish if the recorded events came from the same session. The idea >> is that each time an image is started a new session is created and assigned >> a new UUID. Now when I started to look on the data I noticed that I have >> some cases where I have same session IDs with different session creation >> times (yes a new session is initialized with a current timestamp). The time >> difference for the sessions with the same UUID and a different timestamp is >> within 2 hours. Then another thing that I did is to group the data by the >> timestamp and there are no cases where I have a different ID for the same >> timestamp, which shows that the timestamp is a more reliable ID. Now I will >> deal with my data just fine, but maybe we need to look in the implementation >> why do we get sessions with the same IDs? >> >> Cheers. >> Uko > > I would be very surprised it would happen with NeoUUIDGenerator > (NeoUUIDGenerator next). The idea was to replace UUIDGenerator and the VM > plugin by it. That got stalled when there was unforeseen interaction with > WorkingSession. I believe that should be solved by now. > > Still, UUIDs are not 100% guaranteed to be unique, they are a (very good) > best effort. > > But I agree that if they repeat in such a short time frame, that should be > considered a bug. > > Sven > > > > >
