Session Managers

A session manager automatically creates new session objects whenever a new session starts. In some circumstances, clients do not join the session, for example, if the session manager uses cookies and the client does not accept cookies.

Application Server offers these session management options, determined by the session-manager element’s persistence-type attribute in the sun-web.xml file:

• The memory Persistence Type, the default

• The file Persistence Type, which uses a file to store session data

• The ha Persistence Type, which uses the high-availability database for session persistence

If the session manager configuration contains an error, the error is written to the server log and the default (memory) configuration is used.

The memory Persistence Type

This persistence type is not designed for a production environment that requires session persistence. It provides no session persistence. However, you can configure it so that the session state in memory is written to the file system prior to server shutdown.

To specify the memory persistence type for the entire web container, use the configure-ha-persistence command. For details, see the Sun Java System Application Server Enterprise Edition 8.2 Reference Manual.

To specify the memory persistence type for a specific web application, edit the sun-web.xml file as in the following example. The persistence-type property is optional, but must be set to memory if included. This overrides the web container availability settings for the web application.

<sun-web-app>
...
<session-config>
	<session-manager persistence-type=memory />
		<manager-properties>
			<property name="sessionFilename" value="sessionstate" />
		</manager-properties>
	</session-manager>
	...
</session-config>
...
</sun-web-app>

The only manager property that the memory persistence type supports is sessionFilename, which is listed under manager-properties.

For more information about the sun-web.xml file, see The sun-web.xml File.

The file Persistence Type

This persistence type provides session persistence to the local file system, and allows a single server domain to recover the session state after a failure and restart. The session state is persisted in the background, and the rate at which this occurs is configurable. The store also provides passivation and activation of the session state to help control the amount of memory used. This option is not supported in a production environment. However, it is useful for a development system with a single server instance.

Make sure the delete option is set in the server.policy file, or expired file-based sessions might not be deleted properly. For more information about server.policy, see The server.policy File.

To specify the file persistence type for the entire web container, use the configure-ha-persistence command. For details, see the Sun Java System Application Server Enterprise Edition 8.2 Reference Manual.

To specify the file persistence type for a specific web application, edit the sun-web.xml file as in the following example. Note that persistence-type must be set to file. This overrides the web container availability settings for the web application.

<sun-web-app>
...
<session-config>
	<session-manager persistence-type=file>
		<store-properties>
			<property name=directory value=sessiondir />
		</store-properties>
	</session-manager>
	...
</session-config>
...
</sun-web-app>

The file persistence type supports all the manager properties listed under manager-properties except sessionFilename, and supports the directory store property listed under store-properties.

For more information about the sun-web.xml file, see The sun-web.xml File.

The ha Persistence Type

The ha persistence type uses the high-availability database (HADB) for session persistence. The HADB allows sessions to be distributed. For details, see Distributed Sessions and Persistence. In addition, you can configure the frequency and scope of session persistence. The HADB is also used as the passivation and activation store. Use this option in a production environment that requires session persistence.

The HADB must be configured and enabled before you can use distributed sessions. For configuration details, see the description of the configure-ha-cluster command in the Sun Java System Application Server Enterprise Edition 8.2 Reference Manual.

To enable the HADB, select the Availability Service component under the relevant configuration in the Administration Console. Check the Instance Level Availability box. To enable availability for the web container, select the Web Container Availability tab, then check the Availability Service box. For details, see the Sun Java System Application Server Enterprise Edition 8.2 High Availability Administration Guide.

To change settings such as persistence frequency and persistence scope for the entire web container, see the description of the configure-ha-persistence command in the Sun Java System Application Server Enterprise Edition 8.2 Reference Manual.

To specify the ha persistence type for a specific web application, edit the sun-web.xml file as in the following example. Note that persistence-type must be set to ha. This overrides the web container availability settings for the web application.

<sun-web-app>
...
<session-config>
	<session-manager persistence-type=fileha>
		<manager-properties>
			<property name=persistenceFrequency value=web-method />
		</manager-properties>
		<store-properties>
			<property name=persistenceScope value=session />
		</store-properties>
	</session-manager>
	...
</session-config>
...
</sun-web-app>

The ha persistence type supports all the manager properties listed under manager-properties except sessionFilename, and supports the persistenceScope store property listed under store-properties.

For more information about the sun-web.xml file, see The sun-web.xml File.