ICriteria does not use Session Cache ?

stalamoni · **Joined:** Fri Jul 29, 2005 10:34 am **Posts:** 25

Hibernate version: 1.2

I can't find anything that explains the relation between ICriteria queries and the session cache.
I've this small example below where I've expected only 1 SELECT statement sent to the database.
I am getting 2 SELECT statements (sql profitler) and that's my problem/question.

As you can see, the session "contains" the retrieved object but when the query is executed again, it look like it's not looking inside the session cache.

Code:

   
  ISession session = SessionFactory.CurrentSession;

   ICriteria criteria = session.CreateCriteria(typeof(Category));
   //criteria.SetCacheable(true);

   criteria.Add(new EqExpression("CategoryID", 1));
   Category category = (Category)criteria.UniqueResult();
   Assert.IsTrue(session.Contains(category));

    // fetch it again .
    Category category2 = (Category)criteria.UniqueResult();
    Assert.AreEqual(category, category2);
 

Note: I've tried to use SetCacheable but i think that's something completelty different than the session cache and it's related to the query cache, which it's not this case.

Note2 : If i replace criteria.UniqueResult() with session.Load() , i get only 1 SELECT (which is what i want but still using ICriteria)

Is this expected behaviour?

karlchu · **Posted:** Sat Sep 29, 2007 8:03 pm

It may seem like you are getting a single entity through your "criteria" object, thus, the cached Category object should be returned. As far as NHibernate is concerned, "criteria" is a query, and query results are not cached in the ISession.

SetCacheable() relates to second-level cache. See here for a brief explanation of the happenings when caching queries:
http://forum.hibernate.org/viewtopic.ph ... 65#2357765

stalamoni · **Joined:** Fri Jul 29, 2005 10:34 am **Posts:** 25

First of all, thanks for your reply.

karlchu wrote:

It may seem like you are getting a single entity through your "criteria" object, thus, the cached Category object should be returned.

Yes, actually the cached object is returned since the objects are the same.

karlchu wrote:

As far as NHibernate is concerned, "criteria" is a query, and query results are not cached in the ISession.

Here is where I got confused. I thought that the ICriteria UniqueResult was a kind of session.Load() , and it's not.

Thanks in advance