IBM Support

PM40451: WLM HIGH CPU AND OOM ON PROXY SERVER UNDER LOAD

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • In a scenario in which a WebSphere Application Server Proxy
    Server has been configured to be able to send many concurrent
    requests and all of these requests are sending a high volume
    of load to the same cluster, a timing window in the Workload
    management (WLM) code may cause high CPU and/or OutOfMemory
    conditions to occur when one or more of the cluster members is
    either shut down or for any other reason removed from the
    HAManager DCS View.
    
    A Heap Dump analysis would show hundreds or thousands of
    RuleEtiquette objects, and the thread dump would also show many
    threads waiting for a lock on a hashmap with the stack including
    one or more of the following lines:
    
    at
    com/ibm/websphere/cluster/topography/DescriptionA.registerNotifi
    cationListener(DescriptionA.java:221(Compiled Code))
    
    at
    com/ibm/ws/cluster/selection/rule/RuleEtiquette.registerNotifica
    tionType(RuleEtiquette.java:278(Compiled Code))
    
    at
    com/ibm/ws/cluster/selection/rule/RuleEtiquette.triggerRuleUpdat
    e(RuleEtiquette.java:196(Compiled Code))
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server V8.0                                 *
    ****************************************************************
    * PROBLEM DESCRIPTION: High CPU and/or OutOfMemory conditions  *
    *                      when one or more cluster members        *
    *                      is either shut down or removed from     *
    *                      the                                     *
    *                      HAManager DCS View.                     *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    In a scenario in which a WebSphere Application Server Proxy
    Server has been configured to be able to send many concurrent
    requests and all of these requests are sending a high volume of
    load to the same cluster, a timing window in the WLM code may
    cause high CPU and/or OutOfMemory conditions to occur when one
    or more of the cluster members is either shut down or for any
    other reason removed from the HAManager DCS View.
    A Heap Dump analysis would show hundreds or thousands of
    RuleEtiquette objects, and the thread dump would also show many
    threads waiting for a lock on a hashmap with the stack
    including
    one or more of the following lines:
    at
    com/ibm/websphere/cluster/topography/DescriptionA.registerNotifi
    cationListener(DescriptionA.java:221(Compiled Code))
    at
    com/ibm/ws/cluster/selection/rule/RuleEtiquette.registerNotifica
    tionType(RuleEtiquette.java:278(Compiled Code))
    at
    com/ibm/ws/cluster/selection/rule/RuleEtiquette.triggerRuleUpdat
    e(RuleEtiquette.java:196(Compiled Code))
    

Problem conclusion

  • Synchronization was added around the instantiation of a WLM
    component class, to ensure there are not more instances than
    needed of the RuleEtiquette objects.
    
    The fix for this APAR is currently targeted for inclusion in
    fix pack 8.0.0.1.  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

    PM40451

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-05-31

  • Closed date

    2011-07-25

  • Last modified date

    2011-07-25

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

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

Fix information

  • Fixed component name

    WEBS APP SERV N

  • Fixed component ID

    5724H8800

Applicable component levels

  • R800 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":"8.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
27 October 2021