On Mon, Apr 19, 2010 at 1:10 PM, reindyr <rein...@gmail.com> wrote: > Hi, > > I am using django with Apache and mod_python. I have implemented a > site navigation using the django-nav module. Internally the module > maintains a dictionary and uses templatetags to generate the desired > code for the navigation. > > Now, if I create new model instances in the django admin, I want this > changes to be reflected in the navigation. Therefore I have connected > a signal: > > signals.post_save.connect(post_save, sender=Track) > > and the post_save method modifies the dictionary for the navigation. > > All works well as long as I use the development server. If I switch to > Apache I have the problem, that my view is not always updated. That > means, If I keep hitting F5 in the browser, sometimes I get the old > view, and sometimes I see the new updated view. > > I suspect, it could be a problem that apache starts multiple kernel > threads. I would except, that the database trigger is executed in all > instances, but I am not sure. For testing, I have created debug output > using pythons logging facility and the post_save method is indeed only > executed once. > > I have absolutely no idea where I should look now and would greatly > appreciate any hints that point me in the right direction. > > Cheers, > > Thorsten >
Your conclusions are spot on, which leads to the actual issue - caching in the wrong place. By storing the navigation data in a per-process dictionary, it works perfectly when running as a single process, and less than good in a multi process environment. You need to pull it out of the process, and store it somewhere accessible to all processes, eg in a memcached instance, for example, or not bother caching it at all, and re-calculate on each request (less nice!). Cheers Tom -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
