transaction isolation with ejb3

linux__rulez · **Joined:** Tue Mar 07, 2006 7:20 am **Posts:** 16

I'm using Hibernate with default EntityManager in J2SE with PersistenceContextType Transaction instead of Extended.

I posted a lot about that already in this poll: http://forum.hibernate.org/viewtopic.php?t=956814 so make sure you read that as well. (it became off topic)

Now my questions is regarding the transaction isolation setting that Hibernate should configure via JDBC.

It is clearly stated that EJB3 implementations should default to a "read commited" transaction isolation" to implement a default optimistic concurrency control.

I think this goes against the statement of the Hibernate documentation. Here's the quote (from http://www.hibernate.org/hib_docs/entitymanager/reference/en/html/transactions.html):

Quote:

Hibernate Entity Manager only adds automatic versioning but does not lock objects in memory or change the isolation level of your database transactions.

Now what if I want that read commited isolation, can I specify it somewhere? Is it a bug now?

(for those who did not read my previous posts, I'm using MSSQL2000 and jTDS)

I'd like to welcome any suggestions and/or thoughts

emmanuel · **Posted:** Sat Mar 25, 2006 9:35 am

The spec expect a read commited isolation level for optimistic locking, it does not mandates. You can chose the isolation level you want.

hibernate.connection.isolation

Check the hibernate core ref doc for more infos

linux__rulez · **Joined:** Tue Mar 07, 2006 7:20 am **Posts:** 16

OK thanks,

I'll add these lines to my persistence.xml (in a J2SE app, for an Application Server you will need to setup it elsewere)

<property name="hibernate.connection.isolation" value="2"/>


This should do TRANSACTION_READ_COMMITTED.

I think lots of othere people may want to do the same. See Hibernate in Action, chapter 5, Transactions, Concurrency and Caching