Sun Microsystems Sun GlassFish Enterprise Server 2.1 Tuning Manual page 41

...
</cmp-field-mapping>
<consistency>
<check-version-of-accessed-instances>
<column-name>OrderTable.VC_VERSION_NUMBER</column-name>
</check-version-of-accessed-instances>
</consistency>
</entity-mapping>
In addition, you must establish a trigger on the database to automatically update the version
column when data in the specified table is modified. The Application Server requires such a
trigger to use version consistency. Having such a trigger also ensures that external applications
that modify the EJB data will not conflict with EJB transactions in progress.
For example, the following DDL illustrates how to create a trigger for the Order table:
CREATE TRIGGER OrderTrigger
BEFORE UPDATE ON OrderTable
FOR EACH ROW
WHEN (new.VC_VERSION_NUMBER = old.VC_VERSION_NUMBER)
DECLARE
BEGIN
:NEW.VC_VERSION_NUMBER := :OLD.VC_VERSION_NUMBER + 1;
END;
Request Partitioning
Request partitioning enables you to assign a request priority to an EJB component. This gives
you the flexibility to make certain EJB components execute with higher priorities than others.
An EJB component which has a request priority assigned to it will have its requests (services)
executed within an assigned threadpool. By assigning a threadpool to its execution, the EJB
component can execute independently of other pending requests. In short, request partitioning
enables you to meet service-level agreements that have differing levels of priority assigned to
different services.
Request partitioning applies only to remote EJB components (those that implement a remote
interface). Local EJB components are executed in their calling thread (for example, when a
servlet calls a local bean, the local bean invocation occurs on the servlet's thread).
▼
To enable request partitioning
Configure additional threadpools for EJB execution using the Admin Console.
1
Add the additional threadpool IDs to the Application Server's ORB.
2
You can do this by editing the domain.xml file or through the Admin Console.
Chapter 2 • Tuning Your Application
EJB Performance Tuning
41