Hi all !
I'm trying to use second-level cache in NHibernate .
As it discribed here http://wiki.nhibernate.org/display/NHC/SysCache+Usage.
I use the following description in nhibernate config file :
<property name="hibernate.cache.provider_class">NHibernate.Caches.SysCache.SysCacheProvider,NHibernate.Caches.SysCache</property>
<property name="relativeExpiration">5000</property>
<property name="hibernate.cache.use_query_cache">true</property>

Farther i use <cache usage="read-write"/> in mapping files. Then i'm geting exception NHibernate.MappingException: duplicate cache region.
Did anybody face this problem ? What is my mistake ?
Thx !

How are you getting data from nHibernate?

Clare

What do you mean ? I do it using ICriteria

So you are creating a query?

If so you need to use the query cache.

criteria.SetCacheable(true);
criteria.SetTimeout(300);

Clare

Thanks !
But in which case should i use <cache usage="read-write" /> in mapping files ?

I am still trying to figure out using the second level cache myself. I think that the only time that comes into play is when objects are loaded in nHibernate without using a query like by using a Load or a Get.

Clare

No, there is a difference between the entities cache and the query cache.
The query cache only saves the ids of the entities in the query.
The entities cache saves all the data about them.
The idea here is that a query usually goes to the DB, since that is the authoritative source in the matter, and as long as it goes there, it can get the most recent versions of the entities.