10.3 Web Cache and Forms Integration

Oracle Web Cache can be used as a load balancer with Oracle Forms applications.

The following setup instructions assume the following:

1. Oracle Application Server Web Cache instance running on Host A

2. Oracle HTTP Server instance and OC4J instance on Host B running Oracle Forms application D

3. Oracle HTTP Server instance and OC4J instance on Host C running Oracle Forms application D

Note that there could be more Oracle HTTP Server/OC4J instances, but only two instance pairs will be described here for purposes of simplification. The Oracle HTTP Server/OC4J instances are not clustered because Oracle Forms applications cannot take advantage of Oracle Application Server clustering.

Also note that a Web Cache 9.0.2.x cluster cannot be used. An Oracle Application Server Web Cache cluster can be used to load balance Oracle Forms starting with Oracle Application Server.

Since Forms applications are stateful, Web Cache must be configured for stateful load balancing using its session binding feature.

Configure Web Cache on Host A with the appropriate Site information for the Forms application, as well as Origin Server and Site-to-Server Mapping information for the Oracle HTTP Server instances running on Hosts B and C. When configuring Origin Server information for Hosts B and C, be sure to configure a ping URL that will detect whether Forms application D is running, for example, /forms/frmservlet?ifcmd=status.

To Configure Session Binding in Web Cache: 

1. Add the following code to the orion-web.xml file located in $ORACLE_HOME\j2ee\OC4J_BI_Forms\application-deployments\formsapp\formsweb\orion-web.xml:

   <session-tracking
    cookies="enabled">
   </session-tracking>
   
   

2. Issue this command:

   dcmctl updateconfig -ct oc4j

3. Restart OC4J_BI_Forms with:

   opmnctl restartproc gid="OC4J_BI_Forms"

4. Log on to the Web Cache Manager.

5. In the navigator pane, select Origin Servers, Sites, and Load Balancing |Session Binding.

6. In the Session Binding screen, select Default Session Binding, then select Edit Selected.

7. The Edit Session Binding dialog box appears.

8. From the Please select a session: pull-down list, select JSESSIONID.

9. Select Cookie-based as the session binding mechanism from the dropdown list for Oracle Forms application D.

10. Click Submit.

11. Apply changes and restart Oracle Application Server Web Cache.

To test the setup: 

1. Using a browser, point it to the Web Cache host and access Oracle Forms application D. Ensure that the application works as expected. Keep the browser window open.

2. Identify the Oracle HTTP Server/OC4J that handled the requests. For example, assume this is Host B and shut down the Oracle HTTP Server/OC4J on that host. Now only the Oracle HTTP Server/OC4J running on Host C will be accessible.

3. Using the same browser that is running the Oracle Forms client, access Oracle Forms application D again. The request will fail, and the Forms client will lose its session. Remember that Oracle Forms session state is not replicated among OC4J instances.

4. Next, use the browser to start a new Forms session. Web Cache will direct the requests to the remaining Oracle HTTP Server/OC4J running on Host C. Ensure that the application works as expected.

5. Restart the Oracle HTTP Server/OC4J on Host B. Using a browser, log on to the Web Cache Manager. In the navigator pane, select Monitoring | Health Monitor.

6. On the Health Monitor screen, make sure that Host B is marked UP.

For additional information about Web Cache, see Oracle Application Server Web Cache Administrator's Guide.