Caching objects and stuff in NHibernate

Question

I've written my own caching layer for my objects that come out of data access. My reasoning here is I'd like my data access layer to do just that -- data access. I don't really want it to worry about caching, and I'd only like to go in to that layer when I need to fetch data out of the database. Perhaps this is not the right way to think about things -- please let me know if I'm off track.

Anyway, there is at least one issue that I've ran in to so far. In one scenario, I load an object from NHibernate and stick it in the cache in one request. In the next request I get that object from the cache, modify it, and go back down to NHibernate to save it. Obviously NHibernate pukes, in this particular instance with a "Illegal attempt to associate a collection with two open sessions" exception.

So my question is, I guess, is there anything I should be aware of or do to make this work? Or should I just use a 2nd level cache that's built in to NHibernate?

Answer 1

NHibernate has caching for a reason.. use it :)

You'll find there are quite a few options for a second level cache provider that give you much more flexibility for cheaper then you could build it yourself. A perfect example is something like memcache if you decide you need to run a service on multiple systems.