On Mon, Oct 18, 2010 at 8:53 AM, Vincent Pelletier <vinc...@nexedi.com> wrote: > Hi. > > During my presentation of NEO at DZUG, Cristian Theune told me that I might be > confusing tids and serials. And indeed, I could not define the difference > between them.
I wonder what he meant. > Then I thought about it, and I came to the idea that one of them is only valid > during some time (probably only during 2PC) while the other is persistently > valid. In early versions of ZODB, serials and tids weren't known to be the same, which is why we have _p_serial rather than _p_tid. With experience, we've found that they really are the same. > This means that having just the persistent one is not incorrect, but might add > bigger constraints on transaction commit order (transaction number cannot > decrease, etc), explaining why we don't see any "persistent problem" (data > corruption, etc) when misused. Serial and tid are the same and tids must be monotonically increasing. > Is this right ? Probably not. I'm not sure what you were saying, but if it was based on the premise that tids and serials are different, then it's wrong. :) > If there is any documentation on this ? The doc strings in ZODB/interfaces.py mention in many places that serial is an alias for tid. Jim -- Jim Fulton _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
