Configure write contents

Configure write contents

In session management, we can configure which session data is written to the database or to another WebSphere instance, depending on whether we are using database persistent sessions or memory to memory replication. We can either write only session data properties that have been updated through setAttribute method and removeAttribute method calls or we can write all session data properties.

This flexibility allows for fewer code changes for the JavaServer Pages (JSP) writer when the application will be operating in a clustered environment. The following options are available in Session Management for tuning what is written back:

Write changed (the default) - Write only session data properties that have been updated through setAttribute method and removeAttribute method calls.
Write all - Write all session data properties.

The Write all setting might benefit servlet and JSP writers who change Java objects' states that reside as attributes in HttpSession and do not call HttpSession.setAttribute method.

However, the use of Write all could result in more data being written back than is necessary. If this situation applies to you, consider combining the use of Write all with Time-based write to boost performance overall. As always, be sure to evaluate the advantages and disadvantages for our installation.

With either Write Contents setting, when a session is first created, complete session information is written, including all of the objects bound to the session.

Write Contents setting Behavior with single-row schema Behavior with multirow schema
Write changed If any session attribute is updated, all objects bound to the session are written. Only the session data modified through setAttribute method or removeAttribute method calls is written.
Write all All bound session attributes are written. All session attributes that currently reside in the cache are written. If the session has never left the cache, all session attributes are written.

Tasks

Go to the appropriate level of Session Management.
Click Distributed environment settings
Click Custom tuning parameters.
Click Custom settings.
Select the appropriate write contents setting.
Click OK.

Session management tuning

Write Contents setting	Behavior with single-row schema	Behavior with multirow schema
Write changed	If any session attribute is updated, all objects bound to the session are written.	Only the session data modified through setAttribute method or removeAttribute method calls is written.
Write all	All bound session attributes are written.	All session attributes that currently reside in the cache are written. If the session has never left the cache, all session attributes are written.