Comments on: Caching Layer for Django ORM http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html A blog about Django, JavaScript, CSS, and general web development. Mon, 08 Sep 2008 11:21:32 +0000 http://wordpress.org/?v=2.6.1 By: John http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-18365 John Thu, 28 Feb 2008 21:18:30 +0000 http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-18365 I had some difficulty getting this to work out of the box with the OneToOneRelation (I know it's not exactly in wide use, but until I have model-inheritance, it's the best fit for several aspects of my data model), and with Generic Relations. After a couple tweaks to the code to get it to run (which could very well have broken it), I was finding on average the number of queries required to generate my pages went down by 1-3, and the effect was negligible. For this test, I simply changed all of my models to inherit from CachedModel instead of models.Model. I had some difficulty getting this to work out of the box with the OneToOneRelation (I know it’s not exactly in wide use, but until I have model-inheritance, it’s the best fit for several aspects of my data model), and with Generic Relations.

After a couple tweaks to the code to get it to run (which could very well have broken it), I was finding on average the number of queries required to generate my pages went down by 1-3, and the effect was negligible. For this test, I simply changed all of my models to inherit from CachedModel instead of models.Model.

]]> By: David http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16920 David Thu, 24 Jan 2008 00:49:24 +0000 http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16920 We did tests showing a 2x-5x increase in time for a standard cache call of 10-50 objects. It will be a little bit higher of course with the overhead of iterating through loops, but all in all it's going to provide a means of invalidation and still be far more efficient than SQL. We did tests showing a 2x-5x increase in time for a standard cache call of 10-50 objects. It will be a little bit higher of course with the overhead of iterating through loops, but all in all it’s going to provide a means of invalidation and still be far more efficient than SQL.

]]> By: Al http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16884 Al Tue, 22 Jan 2008 11:46:11 +0000 http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16884 David, While I expect you haven't done any in depth performance testing - have you given it any sort of a work out to give some sort of an indication of the possible benefits this is going to yield for you? Al. David,

While I expect you haven’t done any in depth performance testing - have you given it any sort of a work out to give some sort of an indication of the possible benefits this is going to yield for you?

Al.

]]> By: David http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16877 David Tue, 22 Jan 2008 06:24:43 +0000 http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16877 One quick note is that I haven't actually put much thought into optimizing counts. And it currently doesn't invalidate them. One quick note is that I haven’t actually put much thought into optimizing counts. And it currently doesn’t invalidate them.

]]> By: Jan Oberst http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16876 Jan Oberst Tue, 22 Jan 2008 05:47:42 +0000 http://www.davidcramer.net/code/73/caching-layer-for-django-orm.html#comment-16876 I like this a lot! When I started developing my django app most pages made like 50 seperate foreign key requests each for a single ID to the database. I even had queries for the same ID. Because I really have to focus on DB speed I can't use Django's select_related function. That's why I'm now caching foreign key lookups with memcache get_many calls (Just hacked this code direclty editing Django sources for now). I had most problems with foreign key lookups and obviously count() queries - and it's amazing to have Django's ORM to manage all that caching transparently behind the scenes. Great job! I like this a lot! When I started developing my django app most pages made like 50 seperate foreign key requests each for a single ID to the database. I even had queries for the same ID.

Because I really have to focus on DB speed I can’t use Django’s select_related function. That’s why I’m now caching foreign key lookups with memcache get_many calls (Just hacked this code direclty editing Django sources for now).

I had most problems with foreign key lookups and obviously count() queries - and it’s amazing to have Django’s ORM to manage all that caching transparently behind the scenes. Great job!

]]>