IC64884: Multi-threaded C++ application fails to exploit connection cache in MQ leading to increased chance of IC64690 occurring.

WebSphere MQ V7.0 Fix Pack 7.0.1.2
WebSphere MQ V7.0.1 for i5/OS Fix Pack 7.0.1.2

APAR status

• Closed as program error.

Error description

• A multi-threaded C++ client application creates many
  connections to the same queue manager with the same connection
  details across many threads. This could result in the symptoms
  observed in IC64690. If IC64690 is observed, this APAR should
  also be applied as it addresses conditions which increase the
  chance that IC64690 occurs.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Any users of WebSphere MQ using multi-threaded C++ client
  applications.
  
  Platforms affected:
  Windows
  
  ****************************************************************
  PROBLEM SUMMARY:
  The problem was caused by an uninitialised MQCD structure being
  passed from the C++ layer to the C layer. Due to the
  uninitialised data, this was causing the caching algorithm to
  fail to find a MQCD match in the list of existing connections,
  despite the connection details being identical. This was then
  leading to the unnecessary creation of new cache items, one of
  the conditions which triggers IC64690 to occur.
  

Problem conclusion

• WebSphere MQ was modified to ensure that the MQCD was
  initialised correctly within the C++ layer, thus allowing the
  cache comparison algorithm to correctly ascertain whether a
  similar connection was already in use.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v7.0
  Platform           Fix Pack 7.0.1.2
  --------           --------------------
  Windows            U200316
  
  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:

• 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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