Using different isolation levels on different nodes?

[austvold]

Hi,

I'm using JbossCache 1.1 as a transactional cache for Hibernate 2.1.6. Currently we're running on Tomcat 4.1.30 with JOTM 1.5.3 as the TransactionManager. Database is Oracle 10g.

Frequently, Hibernate is running into deadlock-situations with TImeoutException as a result while putting data into any of the two nodes (or their children):

//net/sf/hibernate/cache/StandardQueryCache
//net/sf/hibernate/cache/UpdateTimestampsCache

From a discussion on the Hibernate forum

http://forum.hibernate.org/viewtopic.php?t=931969&highlight=timeoutexception+query+cache

I see that neither of these paths must be in a transactional context. Gavin King notes that

"Oh, you never explained that this is with the query cache. You will need to put the JBoss query cache region in some kind of nonstransactional mode. Not sure how to do this, ask Ben Wang."

Is it possible to specify separate isolation levels on different nodes?

My current solution is to utilize an extended TreeCacheProvider and TreeCache wrapper in hibernate where two instances of the cache is created. One with isolation level set to REPEATABLE_READ and the other with isolation level NONE.

Best regards,
Ørjan

[belaban]

An isolation level is per TreeCache, you cannot define separate isolation levels for separate regions inside the same TreeCache.
This is a deficiency (IMO) of JTA. You *could* set the isolation level in JDBC per transaction*, but you cannot do this using J2EE transactions.

Bela