2.3 Using a Stateless Object Model

This section describes how object state management is used with the Registrar and Teller objects in the Production sample applications to increase the application’s scalability. For an introduction to object state management, see Using Object State Management.

To increase scalability, the Registrar and Teller objects are configured in the Production server application with the method activation policy. The method activation policy assigned to these two objects results in the following behavior changes:

• Whenever these objects are invoked, they are instantiated by the Oracle Tuxedo domain in the appropriate server group.
• After the invocation is complete, the Oracle Tuxedo domain deactivates these objects.

With the Basic through the Wrapper sample applications, the Registrar object was process-bound (process activation policy). All client requests on the Registrar object invariably went to the same object instance in the memory of the server machine. The Basic sample application design may be adequate for a small-scale deployment. However, as client application demands increase, client requests on the Registrar object eventually become queued, and response time drops.

However, when the Registrar and Teller objects are stateless (method activation policy), and the server processes that manage these objects are replicated, the Registrar and Teller objects can process multiple client requests in parallel. The only constraint on the number of simultaneous client requests that these objects can handle is the number of server processes that are available that can instantiate the Registrar and Teller objects. These stateless objects, thereby, make for more efficient use of machine resources and reduced client response time.

Most importantly, so that Oracle Tuxedo CORBA can instantiate copies of the Registrar and Teller objects in each of the replicated server processes, each copy of these objects must be unique. To make each instance of these objects unique, the factories for those objects must assign unique object IDs to them.

For the Oracle Tuxedo application to instantiate copies of the Registrar and Teller objects in each of the replicated server application processes, each copy of the Registrar and Teller objects have an unique object ID (OID). The factories that create these objects are responsible for assigning them unique OIDs. For information about generating unique object IDs, see Creating CORBA Server Applications. For more information about other design considerations, see Additional Design Considerations.