Simon Willison's Weblog: ormcaching

Cache Machine: Automatic caching for your Django models

2010-03-11T19:35:32+00:00

Cache Machine: Automatic caching for your Django models

This is the third new ORM caching layer for Django I’ve seen in the past month! Cache Machine was developed for zamboni, the port of addons.mozilla.org to Django. Caching is enabled using a model mixin class (to hook up some post_delete hooks) and a custom caching manager. Invalidation works by maintaining a “flush list” of dependent cache entries for each object—this is currently stored in memcached and hence has potential race conditions, but a comment in the source code suggests that this could be solved by moving to redis.

Tags: cachemachine, caching, django, memcached, mozilla, orm, ormcaching, python, redis

Announcing django-cachebot

2010-03-06T12:48:39+00:00

Announcing django-cachebot

The ORM caching space around Django is heating up. django-cachebot is used in production at mingle.com and takes a more low level approach to cache invalidation than Johnny Cache, enabling you to specifically mark the querysets you wish to cache and providing some advanced options for cache invalidation. Unfortunately it currently relies on a patch to Django core to enable its own manager.

Tags: cachebot, caching, django, mingle, orm, ormcaching

Johnny Cache

2010-02-28T22:55:15+00:00

Johnny Cache

Clever twist on ORM-level caching for Django. Johnny Cache (great name) monkey-patches Django’s QuerySet classes and caches the result of every single SELECT query in memcached with an infinite expiry time. The cache key includes a “generation” ID for each dependent database table, and the generation is changed every single time a table is updated. For apps with infrequent writes, this strategy should work really well—but if a popular table is being updated constantly the cache will be all but useless. Impressively, the system is transaction-aware—cache entries created during a transaction are held in local memory and only pushed to memcached should the transaction complete successfully.

Tags: caching, databases, django, memcached, orm, ormcaching, performance, python

Caching Layer for Django ORM

2008-01-23T15:18:19+00:00

Caching Layer for Django ORM

Interesting extension to Django’s ORM that adds automatic caching of querysets and smart cache invalidation.

Tags: caching, david-cramer, django, orm, ormcaching, python