On Mon, Oct 19, 2009 at 6:52 PM, mt <michael.thornh...@gmail.com> wrote: > > Hi All, > I recently upgraded a high traffic site from django 1.0 to django > 1.1.1 and noticed that the load on the server went through the roof, > so I had to revert to django 1.0. > I've done some testing and noticed that the caching behaviour between > 1. 0 and 1.1.1 has changed. > Basically I was caching expensive database queries using memcached, in > django 1.0 reading from the cache is a fast operation however in > django 1.1.1 reading from cache causes all fields with a callable as > default to be called. > In the case where that callable is an expensive operation the > performance is severely affected. > I've created patches showing this regression for the branches > http://code.djangoproject.com/svn/django/branches/releases/1.0.X > and > http://code.djangoproject.com/svn/django/branches/releases/1.1.X > which shows the default callable being called on cache read. > > My questions are: > 1. Is it wrong to store querysets in the cache?
Strictly, a queryset doesn't contain *any* data - it's just a programatic representation of a SQL query. So, putting a queryset in the cache doesn't inherently mean that anything is being stored. However, if the queryset has been evaluated, there might be something in the queryset's internal result cache, and *that* value will be returned when the value is retrieved from the cache. > 2. Should I log a bug for this in the django tracker and upload my > test case patches? Certainly. > 3. Was this change made on purpose to fulfill other features? I can't think of any obvious reason that you would see a regression of that sort - the core infrastructure for queries didn't change between v1.0 and v1.1. There were some features added (such as aggregates), and some cleanup of the internals of value_list() and values() querysets, but those changes shouldn't have affected caching behaviour. Yours, Russ Magee %-) --~--~---------~--~----~------------~-------~--~----~ 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 django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
