IBM Support

PK48101: NEWLY SPAWNED WEBSERVER PROCESSES BREAK SESSION AFFINITY WHEN MEMORY-TO-MEMORY PERSISTENCE IS CONFIGURED.

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • Requests that cross between process within IHS will not
    have affinty honored as it does when staying within the
    same process.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: Users of IBM WebSphere Application Server    *
    *                 versions 6.0.2 and 6.1 Plug-In with          *
    *                 Memory-to-memory Session Management          *
    *                 configured (High Availability Manager's      *
    *                 Partition Table) to maintain session         *
    *                 affinity between browsers and WebSphere      *
    *                 Application Server                           *
    *                                                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: The Plug-in could break an established  *
    *                      session when a newly spawned web        *
    *                      server process handles its first        *
    *                      request. This is due to the fact that   *
    *                      the new process does not have a         *
    *                      stored partition at creation.           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    *                                                              *
    ****************************************************************
    WebSphere Plug-in uses the default load balancing algorithm
    when a new webserver process handles an affinity request.
    Plug-in reports that the partition table is missing and hence
    uses round robin or random load balancing.
    This could potentially lead to loss of session if session data
    is not fully replicated over the cluster.
    

Problem conclusion

  • The plug-in has been enhanced to pre-fetch the partition
    table, so that affinity requests are maintained. A new custom
    property, GetDWLMTable, has been added to web servers which
    enables or disables the plug-in's ability to prefetch the
    Partition Table. To enable this feature, set GetDWLMTable=true,
    regenerate the plugin-cfg.xml for the web server and propagate.
    The default value is FALSE. This custom property is required
    only when Memory-to-Memory Session Management is configured on
    WebSphere Application Server.
    
    
    To add a custom property, please follow the steps below
    1. In the administrative console, select Servers > Web
       Servers > Web_server_name > Plug-in properties > Custom
       properties > New
    2. Under General Properties specify the name of the custom
       property in the Name field (GetDWLMTable) and a value for
       this property in the Value field (true or false). You can
       also specify a description of this property in the
       Description field.
    3. Click Apply or OK.
    4. Click Save to save your configuration changes.
    5. Re-generate & propagate the plugin-cfg.xml.
    
    This fix is scheduled to be released in fix packs 6.0.2.23 and
    6.1.0.13.
    Please refer to the recommended updates page for delivery
    information:
    http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
    

Temporary fix

Comments

APAR Information

  • APAR number

    PK48101

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    60S

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2007-06-29

  • Closed date

    2007-08-20

  • Last modified date

    2007-10-24

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Modules/Macros

  • PLUGIN
    

Fix information

  • Fixed component name

    WEBS APP SERV N

  • Fixed component ID

    5724H8800

Applicable component levels

  • R60A PSY

       UP

  • R60H PSY

       UP

  • R60I PSY

       UP

  • R60P PSY

       UP

  • R60S PSY

       UP

  • R60W PSY

       UP

  • R60Z PSY

       UP

  • R61A PSY

       UP

  • R61H PSY

       UP

  • R61I PSY

       UP

  • R61P PSY

       UP

  • R61S PSY

       UP

  • R61W PSY

       UP

  • R61Z PSY

       UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
29 December 2021