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PM79340: STORAGE LEAK OF X'48 BYTES IN SINGLE SERVANT ENVIRONMENT

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • x'48' or 72 byte storage is leaked when creating HTTP session.
    This affects only servers in a single Servant environment.  The
    problem does not exist for multiple Servant environments.
    
    Sample storage:
    00000000  00000002  00000000  00000002 | ................ |
    B1234567  A681C7C8  00000000  00000048 | .#Eg...........H |
    00000000  7CB76FD2  00000048  0B2184D0 | ....|.o....H.!.. |
    00000000  00000048  43413838  44434143 | .......HCA88DCAC |
    34424443  35333835  30303030  30304538 | 4BDC5385000000E8 |
    30303030  30303032  30393241  37364530 | 00000002092A76E0 |
    2D577971  36714E57  6A7A776B  474C5A73 | -Wyq6qNWjzwkGLZs |
    56305765  4A554200  B7654321  A0C7C226 | V0WeJUB..eC!...& |
    
    LE Heappool trace showed the following code requested this
    storage:
    
    j9mem_allocate_memory_basic
    j9mem_allocate_memory
    jniArrayAllocateMemoryFromThread
    Z_GETSTRINGUTFCHARS
    getStringUTFChars
    Java_com_ibm_ws390_rt_HTTPSessionAffinity_registerSession
    RUNJAVATHREAD
    javaProtectedThreadProc
    j9sig_protect
    javaThreadProc
    
    This problem can manifest itself as much larger storage leak due
    to Java JNI caching being enabled.  For more information on
    -Xjni:arrayCacheMax, refer to this DOC apar PM79234.
    

Local fix

  • local work-around of setting
    Servers --> Application Servers --> <YOUR_SERVER> -->
    Java and Process Management --> Server Instance -->
    Multiple Instances Enabled (check the box).
    If you check that box but leave min/max Servants set to 1/1,
    
    this will cause the server to run in a multiple Servant
    environment that happens to only have 1 Servant,
    which will avoid this issue without actually requiring multiple
    Servants to be running.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server V8.0 and V8.5                        *
    ****************************************************************
    * PROBLEM DESCRIPTION: Native storage leak in WebSphere        *
    *                      Application Server for z/OS servant     *
    *                      process.                                *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Two storage leaks may occur in the servant when configured in
    single server mode (wlm_dynapplenv_single_server=1).
    There are two unique native storage leaks identified by this
    APAR.
    The first leak can occur creating an HTTP Session.  The leak
    has been identified as x'48' bytes obtained using a JNI
    service. The following is an example of an
    instance of this leaked storage:
    00000000 00000048  |................|
    43413543 33373737 38463435 32363833  |CA5C37778F452683|
    30303030 30324143 30303030 30303035  |000002AC00000005|
    30393241 37363634 4C757A69 7569656E  |092A7664Luziuien|
    57626364 30726956 6D70447A 78446C00  |Wbcd0riVmpDzxDl |
    The second leak identified with this APAR occurs when an
    EJB Stateful Object is created in the Single Server mode.
    The leak is typically x'14' bytes in length obtained from the
    LE heap.  It typically contains a UUID value.  The following
    is an example of an instance of this leaked storage:
    CAB64103 ABB3078A 00000180 00000001
    00000000
    

Problem conclusion

Temporary fix

Comments

APAR Information

  • APAR number

    PM79340

  • 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

    2012-12-17

  • Closed date

    2013-01-14

  • Last modified date

    2013-03-18

  • 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



Document information

More support for: WebSphere Application Server for z/OS
General

Software version: 800

Reference #: PM79340

Modified date: 18 March 2013


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