HTTP session problems

 

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1. Overview
2. HTTP Sessions are not getting created, or are lost between requests.
3. HTTP Sessions are not persistent (session data lost when appserver restarts, or not shared across cluster).
4. Session is shared across multiple browsers on same client machine.
5. Session is not getting invalidated immediately after specified session timeout interval.
6. Unwanted sessions are being created by JSP.
7. Session data intended for one client is seen by another client.
8. A ClassCastException error occurs during failover of a session that contains an EJB reference.
9. Users are not logged out after HTTP session timer expires

 

Overview

To update the session manager...

appserver | Additional properties | Web Container | Session manager

See also:

1. Review: HTTP session manager troubleshooting tips
2. Review: Managing HTTP sessions
3. Check available online support
4. Contact IBM support

 

HTTP sessions are not getting created, or are lost between requests

By default, the session manager uses cookies to store the session ID on the client between requests. Unless you intend to avoid cookie-based session tracking, ensure that cookies are flowing between WAS and the browser:

• Make sure the Enable cookies check box is checked under the Session tracking Mechanism property.

• Make sure cookies are enabled on the browser we are testing from or from which the users are accessing the application.

• Check the Cookie domain specified on the SessionManager...

  Session tracking mechanism | enable cookies | Modify

  • For example, if the cookie domain is set as ".myCom.com", resources should be accessed using that domain name. For example:

    http://www.myCom.com/myapp/servlet/sessionservlet

  • If the domain property is set, make sure it begins with a dot (.). Certain versions of Netscape do not accept cookies if domain name doesn't start with a dot. Internet Explorer honors the domain with or without a dot. For example, if the domain name is set to mycom.com, change it to .mycom.com so that both Netscape and Internet Explorer honor the cooki.

    When the servers are on different hosts, ensure that session cookies flow to all the servers by configuring a front-end router such as a Web server with the plug-in or setting the Cookie domain.

• Check the Cookie path specified on the SessionManager. Check whether the problem URL is hierarchically below the Cookie path specified. If not correct the Cookie path.

• If the Cookie maximum age property is set, verify the client (browser) machine's date and time is the same as the server's, including the time zone. If the client and the server time difference is over the "Cookie maximum age" then every access would be a new session, since the cookie expires after the access.

• If we have multiple Web modules within an enterprise application that track sessions:

  • To have different session settings among Web modules in an enterprise application, ensure that each Web module specifies a different cookie name or path, or

  • If Web modules within an enterprise application use a common cookie name and path, verify the HTTP session settings, such as Cookie maximum age, are the same for all Web modules. Otherwise cooki behavior is unpredictable, and depends upon which application creates the session. Note that this does not affect session data, which is maintained separately by Web module.

• Check the cookie flow between browser and server:

  1. On the browser, enable "cookie prompt". Hit the servlet and make sure cookie is being prompted.

  2. On the server, enable SessionManager trace. Enable tracing for the HTTP session manager component, by using the trace spec...
     com.ibm.ws.session.*=all=enabled

     After trace is enabled, exercise the session-using servlet or JSP, then follow the instructions for dumping and browsing the trace output .

  3. Access the session servlet from the browser.

  4. The browser prompts for the cooki; note the jsessionid.

  5. Reload the servlet, note down the cookie if a new cookie is sent.

  6. Check the session trace and look for the session ID and trace the request by the thread. Verify that the session is stable across Web requests:

     • Look for getIHttpsession(...) which is start of session request.

     • Look for releaseSession(..) which is end of servlet request.

• If using URL rewriting instead of cookies:

  • Ensure there are no static HTML pages on the application's navigation path.

  • Verify the servlets and JSPs are implementing URL rewriting correctly. For details and an example see Session tracking options.

• Deprecated feature: Session tracking using the SSL ID is deprecated in WAS version 7.0. Configure session tracking to use cookies or modify the application to use URL rewriting.depfeat If using SSL as the session tracking mechanism:

  • Ensure that we have SSL enabled on the IBM HTTP Server or iPlanet HTTP server.

  • Review Session tracking options.

• If in a clustered (multiple node) environment, ensure that we have session persistence enabled.

 

HTTP Sessions are not persistent

If the HTTP sessions are not persistent, that is session data is lost when the appserver restarts or is not shared across the cluster:

• Check the data source.

• Check the session manager's persistence settings properties:

  • If we intend to take advantage of session persistence, verify that Persistence is set to Database.

  • Persistence could also be set to Memory-to-Memory Replication.

  • If using Database-based persistence:

    • Check the JNDI name of the data source specified correctly on SessionManager.

    • Specify correct userid and password for accessing the database.

      Note that these settings have to be checked against the properties of an existing data source in the admin console. The session manager does not automatically create a session database for you.

    • The data source should be non-JTA, for example, non XA enabled.

    • Check the JVM logs for appropriate database error messages.

    • With DB2, for row sizes other than 4k make sure specified row size matches the DB2 page size. Make sure tablespace name is specified correctly.

  • If using memory-based persistence (available only in a network deployment environment):

    • Review Memory-to-memory replication.

    • Review the Internal Replication Domains properties of the session manager.

 

Session is shared across multiple browsers on same client machine

This behavior is browser-dependent. It varies between browser vendors, and also may change according to whether a browser is launched as a new process or as a subprocess of an existing browser session (for example by hitting Ctl-N on Windows).

The Cookie maximum age property of the session manager also affects this behavior, if cookies are used as the session-tracking mechanism. If the maximum age is set to some positive value, all browser instances share the cookies, which are persisted to file on the client for the specified maximum age time.

 

Session is not getting invalidated immediately after specified session timeout interval

The SessionManager invalidation process thread runs every x seconds to invalidate any invalid sessions, where x is determined based on the session timeout interval specified in the session manager properties. For the default value of 30 minutes , x is around 300 seconds. In this case, it could take up to 5 minutes (300 seconds) beyond the timeout threshold of 30 minutes for a particular session to become invalidated.

 

Unwanted sessions are being created by JSPs

As required by the JSPs specification, JSP pages by default perform a request.getSession(true), so that a session is created if none exists for the client. To prevent JSP pages from creating a new session, set the session scope to false in the .jsp file using the page directive as follows:

<% @page session="false" %>

 

Session data intended for one client is seen by another client

In rare situations, usually due to application errors, session data intended for one client might be seen by another client. This situation is referred to as session data crossover.

When the DebugSessionCrossover custom property is set to true, code is enabled to detect and log instances of session data crossover. Checks are performed to verify that only the session associated with the request is accessed or referenced. Messages are logged if any discrepancies are detected.

These messages provide a starting point for debugging this problem. This additional checking is only performed when running on the WebSphere-managed dispatch thread, not on any user-created threads.

 

Users are not logged out after the HTTP session timer expires

If users of WAS log onto an application and sit idle longer than the specified HTTP session timeout value, the user information is not invalidated and user credentials stay active until LTPA token timeout occurs.

After you apply PK25740, complete the following steps to log out users from the application after the HTTP session has expired.

1. In the admin console, click...

   Security | Global security | Custom properties | New

2. In the Name field, enter...

   com.ibm.ws.security.web.logoutOnHTTPSessionExpire

3. In the Values field, enter true.

4. Click Apply and Save to save the changes to the configuration.

5. Resynchronize and restart the server.

IBM Support has documents and tools that can save you time gathering information needed to resolve problems as described in Troubleshooting help from IBM. Before opening a problem report, see the Support page:

• http://www.ibm.com/software/webservers/appserv/was/support/

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Related concepts Best practices for using HTTP sessions
Sessions

 

Related tasks

Task overview: Managing HTTP sessions

 

Related

HTTP session manager troubleshooting tips