IBM Support

IV16597: WEBSPHERE MQ V7.0JMS CLIENT HANGS IN A FINALIZER THREAD CAUSING AN OUT OF MEMORY CONDITION.

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • An OutOfMemory (OOM) condition is experienced when the heap
    fills up with MessageContext objects using WebSphere MQ classes
    for JMS.  A javacore shows that the finalizer thread stuck
    within the following stack:
    
    "Finalizer thread" J9VMThread:0x0000000030CCF800, j9thread_t:
    0x000000011959EE40, java/lang/Thread:0x0000000040DD60E0,
    state:CW, prio=5
    (native thread ID:0x30A01FB, native priority:0x5, native
    policy:UNKNOWN)
    Java callstack:
    at java/lang/Object.wait(Native Method)
    at java/lang/Object.wait(Object.java:196(Compiled Code))
    at
    com/ibm/mq/jmqi/remote/internal/system/RemoteConnection.sendTSH
    (RemoteConnection.java:2221(Compiled code))
    at
    com/ibm/mq/jmqi/remote/internal/RemoteHconn.sendTSH(RemoteHconn
    .java:1111(Compiled Code))
    at
    com/ibm/mq/jmqi/remote/internal/RemoteFAP.MQDISC(RemoteFAP.java
    :2552(Compiled Code))
    at
    com/ibm/msg/client/wmq/internal/WMQConnection.close(WMQConnecti
    onjava:732(Compiled Code))
    at
    com/ibm/msg/client/jms/internal/JmsConnectionImpl.close(JmsConn
    ectionImpl.java:352(Compiled Code)
    at
    com/ibm/msg/client/jms/internal/JmsConnectionImpl.finalize(JmsC
    onnectionImpl.java:224(Compiled Code))
    at
    java/lang/J9VMInternals.runFinalize(J9VMInternals.java:412(Comp
    iledCode))
    

Local fix

  • Local Fix￘
    Restart JVMs to clear the heap.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of the WebSphere MQ classes for JMS,
    WebSphere MQ classes for Java or WebSphere MQ Resource Adapter,
    who are using a 'REMOTE' (TCP) connection to communicate with
    a queue manager.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows) +Java +Java zOS
    ****************************************************************
    PROBLEM SUMMARY:
    The problem was caused by code that serialized access to certain
    communication functions.  Conditions may arise where a thread
    will lock access but not release, which means that any
    subsequent thread to access the communications object will
    block indefinitely.
    
    This can cause a hang condition, or if the thread that is
    blocked is the finalizer thread, this can prevent the JVM
    garbage collector from running, which will lead to an
    OutOfMemory condition occurring.
    

Problem conclusion

  • The code has been changed to ensure a thread that takes a lock
    will also release it.
    
    As part of the code change, further diagnostics were also added
    to the code base.  If a similar condition occurs again within
    the communication classes, FDC files will be generated which
    have a probeID of:
    
    .          JO215002
    .          JO215003
    
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.9
    --------           --------------------
    Windows            U200337
    AIX                U849391
    HP-UX (PA-RISC)    U849723
    HP-UX (Itanium)    U849728
    Solaris (SPARC)    U849724
    Solaris (x86-64)   U849730
    iSeries            7.0.1.9
    Linux (x86)        U849725
    Linux (x86-64)     U849729
    Linux (zSeries)    U849726
    Linux (Power)      U849727
    zOS                7.0.1.9
    
                       v7.1
    Platform           Fix Pack 7.1.0.2
    --------           --------------------
    Windows            7.1.0.2
    AIX                7.1.0.2
    HP-UX (Itanium)    7.1.0.2
    Solaris (SPARC)    7.1.0.2
    Solaris (x86-64)   7.1.0.2
    iSeries            7.1.0.2
    Linux (x86)        7.1.0.2
    Linux (x86-64)     7.1.0.2
    Linux (zSeries)    7.1.0.2
    Linux (Power)      7.1.0.2
    zOS                7.1.0.2
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV16597

  • Reported component name

    WMQ AIX V7

  • Reported component ID

    5724H7221

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-03-02

  • Closed date

    2012-04-29

  • Last modified date

    2012-04-29

  • 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

    WMQ AIX V7

  • Fixed component ID

    5724H7221

Applicable component levels

  • R701 PSY

       UP

[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSCPQ63","label":"APAR \/ Maintenance"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0.1","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
29 April 2012