Hmmmm... I need to redact my statement about pickling working on the filesystem cache back-end. On one particular Windows development machine it works, but not on a linux box with identical code on Apache.
Which leaves me in an even more strange situation... why does the development server's pickling action act differently than that in Apache's? I don't think it was just failing silently, because I was specifically trying to lower my database query hits while I coded that bit of caching, and it was a major contribution to the effort... Either way, it looks like I'm going to be reworking a piece of my code, since the development server tricked me into thinking that I could pickle those QuerySets. On Feb 24, 8:14 pm, Tim Valenta <tonightslasts...@gmail.com> wrote: > There was a topic on this a couple of years ago, and it seems to still > be around. > (Original:http://groups.google.com/group/django-users/browse_thread/thread/3214...) > > An exception is raised when trying to use the low-level caching API on > a QuerySet. I read from the mentioned thread that pickling the a > QuerySet after the refactor branch was merged has troubles, and as > Malcom has said, it's just straight-up "hard". > > Especially from the documentation's explanation, I can see why it's no > easy task: > > "This means that when you unpickle a QuerySet, it contains the > results at the moment it was pickled, rather than the results that are > currently in the database." > > Is there any hope of this being addressed in the near future? I know > 1.2 is feature-frozen, but what's the likelihood that this is going to > be fixed? Can the documentation on Pickling QuerySets be updated to > actually reflect this issue? The docs don't bring this up at all. > What's worse, is that pickling the QuerySets actually seems to work > just fine with the filesystem caching backend. I can't begin to tell > you how long it took me to figure out the problem. > > So... what's the difference between a pickled QuerySet in a filesystem > cache and a pickled QuerySet in a database cache? It's the same > pickled string in the end. I had a look at the area of code raising > the Exception, and I frankly don't understand what the backend has to > do with that line of code. (http://code.djangoproject.com/browser/ > django/trunk/django/core/cache/backends/db.py line 57) > > This creates annoying trouble for someone like me, trying to use a > database-driven caching system, yet specific parts of my site cannot > use my back-end of choice. > > I've read the workaround of caching the list version of the results, > and I am looking into that. I just want to find out a little more > about what the situation is, two years after that initial thread. > > Tim -- 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.
