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IC61153: WHEN SHARING CONVERSATIONS IS ENABLED, WEBSPHERE MQ V7 JMS APPLICATION THREADS HANG IF THERE ARE CONNECTION PROBLEMS

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APAR status

  • Closed as program error.

Error description

  • When Sharing Conversations is enabled, WebSphere MQ V7
    applications that use the classes for Java Message Service
    (JMS) experience hanging threads if a communications error
    (such as a socket exception) occurs between the application and
    the queue manager. A Javacore taken at the time of the hang
    shows the following stack trace for the hanging threads:
    
    <thread name> (state:CW, pri=5 native thread ID:0x14E8, native
    priority:0x5, native policy:UNKNOWN)
    at java/lang/Object.wait(Native Method)
    at java/lang/Object.wait(Bytecode PC:3)
    at com/ibm/mq/jmqi/remote/internal/RemoteHconn.exchangeTSH()
    at com/ibm/mq/jmqi/remote/internal/system/
    RemoteProxyQueue.requestMessages()
    at com/ibm/mq/jmqi/remote/internal/system/
    RemoteProxyQueue.flushQueue()
    at com/ibm/mq/jmqi/remote/internal/system/
    RemoteProxyQueue.proxyMQGET()
    at com/ibm/mq/jmqi/remote/internal/RemoteFAP.jmqiGetMessage()
    at com/ibm/mq/jmqi/internal/JmqiTools.getMessage()
    at com/ibm/mq/jmqi/remote/internal/RemoteFAP.jmqiGet()
    at com/ibm/msg/client/wmq/internal/WMQConsumerShadow.getMsg()
    at com/ibm/msg/client/wmq/internal/
    WMQSyncConsumerShadow.receiveInternal()
    at com/ibm/msg/client/wmq/internal/WMQConsumerShadow.receive
    at com/ibm/msg/client/wmq/internal/WMQMessageConsumer.receive
    at com/ibm/msg/client/jms/internal/
    JmsMessageConsumerImpl.receiveInboundMessage()
    at com/ibm/msg/client/jms/internal/
    JmsMessageConsumerImpl.receiveNoWait()
    at com/ibm/mq/jms/MQMessageConsumer.receiveNoWait()
    Additional Keywords: Share shared conn SVRCONN server client
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects any application that uses the WebSphere MQ
    V7 classes for JMS to connect to a V7 queue manager over a
    channel that has Sharing Conversations enabled.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows) +Java
    ****************************************************************
    PROBLEM SUMMARY:
    When a request is made from a WebSphere MQ V7 classes for JMS
    application to get a  message from a queue, an initial
    handshake happens between the application and the queue
    manager. During this handshake, the classes for JMS sends TSH
    information to the queue manager and waits for the response.
    
    If the connection between the application and the queue manager
    was broken when the application thread that sent the TSH was in
    a waiting state, the waiting thread was never notified. This
    caused the thread to wait indefinitely and any further
    connection to the queue manager failed.
    

Problem conclusion

  • The WebSphere MQ V7 classes for JMS have been modified so that
    the waiting thread will wait up to 10 seconds for a response
    from the queue manager for a specified period before returning.
    
    If the timeout period elapses, the waiting thread comes back
    and checks for any connection problems. If the connection is
    still up and running, the thread will go back to waiting for a
    response from the queue manager.
    
    The timeout value can be changed by setting the following Java
    System property:
    
    com.ibm.mq.polling.RemoteRequestEntry=<time in milliseconds>
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.0
    --------           --------------------
    Windows            U200306
    AIX                U823774
    HP-UX (PA-RISC)    U823665
    HP-UX (Itanium)    U823667
    Solaris (SPARC)    U823772
    Solaris (x86-64)   U824344
    iSeries            tbc_p700_0_1_0
    Linux (x86)        U823664
    Linux (x86-64)     U823773
    Linux (zSeries)    U823668
    Linux (Power)      U823666
    
    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

    IC61153

  • Reported component name

    WMQ WINDOWS V7

  • Reported component ID

    5724H7220

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-05-18

  • Closed date

    2009-05-29

  • Last modified date

    2009-06-05

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

    IC61101

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

Fix information

  • Fixed component name

    WMQ WINDOWS V7

  • Fixed component ID

    5724H7220

Applicable component levels

  • R700 PSY

       UP

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Document Information

Modified date:
05 June 2009