On Thu, 2007-03-01 at 20:17 -0800, Graham Dumpleton wrote: [...] I wrote: > > > I'm wondering if this may lead to race conditions along the lines of: > > > > > thread A creates a session > > > > > thread B creates a session > > > > > thread A stores "foo = 6" in session > > > > > thread B stores "blah = 1" in its session > > > > > thread A stores session (which contains foo=6) > > > > > thread B stores session (which does NOT have > > > foo=6) > > > > > might be happening if you are doing lots of partial updates. > > This doesn't make sense.
Actually it makes a lot of sense now that I look at the code. > Normally the way sessions work, a second > request is usually locked out until the first request has finished > with the session object and released it. Thus there can be no > overlapping changes unless you are doing silly things like unlocking/ > locking them yourself during a request. At least this is how > mod_python sessions work. How Django sessions (which don't actually > use mod_python sessions) work I don't know. Just to keep things on the right track for debugging Set's problem, I'll note that this isn't correct for Django sessions. As can be seen from the code in django/contrib/sessions/middleware.py and models.py, we don't do any cross-thread or cross-process locking when creating a session instance. Maybe we well should be doing something like that for people who want to do simultaneous updates -- as might happen in an AJAX driven site -- but, right now, we do not. A lot of Django enhancements like this are historically driven by usage patterns: the whole framework was written for one -- fairly broad -- purpose and is gradually and carefully extended to handle other reasonable uses as they come up. This would be a good mini-project for somebody to look at doing if they felt so inclined. A bit of design work would be required, not just a one-line patch, I supsect, but it's not going to be of the "cure cancer" level of difficulty. Regards, Malcolm --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---