Hi,

I am wondering if it is possible to use the query cache for Hibernate when there are different user, with different sessions, that should get different results depending on user.

My application retrieves a list from the database, and this result is hardly ever changed during the user's session. So it should be nice to cache the result of the query. However, the list that is the result is always different between users, and therefore I do not want the cache to be shared between users and sessions.

Regards

Pichdude

From what I understand, when you execute a query Hibernate automatically checks the Session's cache (first-level) to see if it is there. If there is no match then Hibernate checks the second-level cache (EHCache) which contains instances (if it's enabled for the particular Class) from all Sessions that originated from a particular SessionFactory.

Therefore, the first thing that comes to mind is to give each User their own Session and use that Session for all queries from the User. That way, if a User is requesting the List, the Session will check and see if it's cached before it goes to the database. And since each User has their own Session, they should only have a reference to their List and not anyone elses.

I noticed that your post said that Users are using different Sessions but in order for you to properly utilize the caching you might want to see if you can change that. The only other thing I can think about is creating a SessionFactory for each User, as then the second-level cache can be used per User, but that way is horribly inefficient and will eat up a lot more of your resources than the Session-per-User way which doesn't even require using a second-level cache.

Ben

Is the query exactly the same for two different users, or is there a parameter difference?

Say the query is "from AccountTransaction where user=:user", and you call setEntity("user", currentUser). In that case, the query will be placed in the second-level cache separately for each different currentUser, and there's no risk of one user getting another's account history.

Just make sure you cache this query correctly and that you've configured the AccountTransaction entity (or whatever it is you are actually returning) to cache, too.