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PI20914: NATIVE STORAGE LEAK WHEN SMF120 SUB-TYPE9 RECORDING TURNED ON.

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APAR status

  • Closed as program error.

Error description

  • High CPU, excessive GC, java.lang.OutOfMemoryError exceptions
    seen in controller region when SMF recording is turned on for
    SMF120 record subtype 9.
    

Local fix

  • avoid recording SMF-120 subtype9 data until  the official fix
    is applied.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server V8.0 and V8.5                        *
    ****************************************************************
    * PROBLEM DESCRIPTION: A WebSphere Application Server for      *
    *                      z/OS                                    *
    *                      server using Asychronous Beans and      *
    *                      with SMF 120 Subtype 9 CPU recording    *
    *                      enabled receives a                      *
    *                      java/lang/OutOfMemoryError in the       *
    *                      Servant.                                *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When Work submitted to an Asynchronous Beans Work Manager is
    executed, certain RAS information such as whether to record
    SMF data is set onto the thread of execution.  When the Work
    completes, this information is reset to a clean state.  This
    works fine when the Work is executed on a thread in the Work
    Manager's thread pool, however it is possible to submit Work
    to run on the current thread by using the
    com.ibm.websphere.asynchbeans.WorkManager.doWork API.  What
    happens in this case is that after the Work completes and the
    RAS information is reset, control is returned back to the
    code that submitted the Work, but the RAS state is no longer in
    effect.
    When SMF 120 Subtype 9 CPU recording is enabled, this causes a
    memory leak.  Certain objects that contain SMF data are created
    prior to the doWork invocation.  When doWork returns and the
    RAS state has been reset, the SMF objects are not cleaned up.
    This will eventually lead to a
    java/lang/OutOfMemoryError in the Servant.  Analysis of a heap
    dump will show a large number of
    com.ibm.ws390.sm.smf.SmfRequestTracker objects.
    

Problem conclusion

Temporary fix

Comments

APAR Information

  • APAR number

    PI20914

  • Reported component name

    WEBSPHERE FOR Z

  • Reported component ID

    5655I3500

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-06-26

  • Closed date

    2014-07-08

  • Last modified date

    2014-07-08

  • 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

    WEBSPHERE FOR Z

  • Fixed component ID

    5655I3500

Applicable component levels

  • R800 PSY

       UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SS7K4U","label":"WebSphere Application Server for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"800","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
27 April 2022