How to configure jboss for optimistic locking?

[equine]

Hi,
I am using jboss 3.2.1 with bundled tomcat 4.1.24.
If anyone can help me out to configure jboss for optimistic locking.

All the EJB's in my application are CMP. The transactions are long, thus deadlock situation is occuring when two users are trying to access a single bean and going for timeout.

If any other solution is available that will be great.

Thansks in Advance

[nraghuram]

You need to modify the container configuration in jboss.xml and also make changes at the entity level in jbosscmp-jdbc.xml
I am using version based locking (there are other options also like timestamp and modified fields) .

I had to add the foll to each entity which required optimistic locking in jbosscmp-jdbc.xml
<optimistic-locking>
<version-column/>
<field-name>versionNo</field-name>
<column-name>VERSION_NO</column-name>
<jdbc-type>BIGINT</jdbc-type>
<sql-type>NUMBER</sql-type>
</optimistic-locking>

In jboss.xml the foll changes to the container configuration
<locking-policy>org.jboss.ejb.plugins.lock.JDBCOptimisticLock</locking-policy>

hth
raghu

[equine]

Do I need to create any field on database table?

[nraghuram]

yes. in my case i created the VERSION_NO field . but if u are using locking strategy based on modified fields then u dont. for version locking and timestamp based locking u will need the field
raghu