IBM Support

PM42465: Excessive memory usage by XMLStreamReader pool may lead to OutOfMemoryError.

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Excessive memory usage by the IBM StAX implementation may
    result in a java.lang.OutOfMemoryError. The size of the
    cached XMLStreamReader objects may grow without bound. Here is
    a sample heapdump that was collected during a stress test:
    
    1,934,853,366 (94%) [80] 4 array of
    [Lcom/ibm/xml/xlxp2/api/util/Pool$Poolable; 0xfffffffeb1dfa6d8
     531,437,140 (25%) [796] 50
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xfffffffeb1e56ae8
     512,072,055 (24%) [796] 47
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xfffffffeb1dfa740
     474,720,178 (23%) [796] 50
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xfffffffeb1e217d8
     416,623,913 (20%) [796] 51
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xffffffff115d78e0
    

Local fix

  • na
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All IBM WebSphere Application Server V7.0   *
    *                  and V8.0 users of StAX, JAXB and JAX-WS.    *
    ****************************************************************
    * PROBLEM DESCRIPTION: Excessive memory usage by the IBM       *
    *                      StAX implementation may lead to an      *
    *                      OutOfMemoryError.                       *
    ****************************************************************
    * RECOMMENDATION:  Install a fix pack that contains this       *
    *                  APAR.                                       *
    ****************************************************************
    When running a JAX-WS application, a tremendous growth in
    the size of cached XMLStreamReader objects in the heap may be
    observed.
    A heapdump collected from a stress test may look like the
    following:
    1,934,853,366 (94%) [80] 4 array of
    [Lcom/ibm/xml/xlxp2/api/util/Pool$Poolable; 0xfffffffeb1dfa6d8
    531,437,140 (25%) [796] 50
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xfffffffeb1e56ae8
    512,072,055 (24%) [796] 47
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xfffffffeb1dfa740
    474,720,178 (23%) [796] 50
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xfffffffeb1e217d8
    416,623,913 (20%) [796] 51
    com/ibm/xml/xlxp2/api/wssec/WSSXMLStreamReader
    0xffffffff115d78e0
    

Problem conclusion

  • For efficiency the IBM StAX implementation caches
    XMLStreamReader objects in a pool for reuse. This pool may
    retain strong references to XMLStreamReaders which continue to
    grow over time, eventually resulting in an OutOfMemoryError if
    an excessive amount of memory is used by those objects.
    
    A system property called
    com.ibm.xml.xlxp2.api.util.Pool.STRONG_REFERENCE_POOL_MAXIMUM_SI
    ZE is provided by this APAR. Its value is an integer and when
    set, it limits the number of XMLStreamReaders (and
    XMLStreamWriters) that will be cached using strong references.
    
    To avoid the OutOfMemoryError, set the system property to 0.
    This will force all XMLStreamReaders to be cached using
    SoftReferences, allowing the garbage collector to reclaim the
    memory they occupy in the cache at any time.
    
    When the system property is not set its default value is 10.
    
    The fix for this APAR is currently targeted for inclusion in
    fix pack 7.0.0.21 and 8.0.0.2. 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

    PM42465

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-06-27

  • Closed date

    2011-09-14

  • Last modified date

    2011-09-14

  • 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

  • R700 PSY

       UP

  • R800 PSY

       UP



Document information

More support for: WebSphere Application Server
General

Software version: 7.0

Reference #: PM42465

Modified date: 14 September 2011


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