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

WebSphere MQ V7.0 Fix Pack 7.0.1.1
WebSphere MQ V7.0 Fix Pack 7.0.1.2

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 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

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