Sqlcachedependency not invalidating cache ucf dating help
Creating a new cache dependency doesn’t help us much if we can’t get a reference to it later - otherwise, how can we call One quick singleton pattern later and we can call these methods from throughout our codebase.
When we invoke our slow action for the first time we need to add the dependency to the response using a unique key to identify the slow resource: to your controllers instead of accessing it directly, but the singleton will suffice for this example.
If you can say "this can be 5 minutes out of date" at a product level, a lot of cache complexity simply evaporates. Once you add in a few joins ensuring the version is always correct can be hard. NET's Sql Cache Dependency - very useful for cache invalidation, it's been around for while. I would love to be proven wrong about this as I need this functionality bad for the current project I am working on.
This approach works well when you want to cache data from an existing integration database and don't have the luxury of rearchitecting the whole thing.
We're using Twisted and happily mixing queries and NOTIFY.whenever you do a write to your database, you have to think what caches might be depending on your write and you'll have to remember to fire events accordingly. You don't need to think about it when you write. There is another alternative called Sql Dependency which doesn't use polling but it is severely restricted.
This of course has the tendency of being more expensive when reading (because you have to calculate the cache key), but it also has the tendency of being correct with a much greater likelyhood - at least that's the experience I made so far.
The reason is that when you rely on cleaning out caches, then, whenever you do a write to your database, you have to think what caches might be depending on your write and you'll have to remember to fire events accordingly.
It's much easier if you generate some kind of key or tag based on the information you want to cache and then just look up the value based on the key - like what you'd do with memcache.
The trigger-backed cache invalidator was also written in ruby, and knew from rails/cache-money what key(s) needed to be invalidated when it got a notification.
IIRC you didn't need to do anything special when you added a new cache key (e.g.
That’s the lot - now we can manually invalidate our slow resource whenever and from wherever we want, and our users can enjoy speedy cached resources the rest of the time!