IV45181: PERFORMANCE OVERHEAD DUE TO TRACE ALWAYS ENABLED FOR WEBSPHERE MQ V7.1/V7.5 JMS CLASSES IN WEBSPHERE APPLICATION SERVER V6.1

Fix Pack 7.1.0.4 for WebSphere MQ V7.1
WebSphere MQ V7.5 Fix Pack 7.5.0.3

APAR status

• Closed as program error.

Error description

• WebSphere Application Server V6.1 uses the WebSphere MQ JMS
  classes indicated by the MQ_INSTALL_ROOT WebSphere variable.  If
  you update this variable to point to WebSphere MQ V7.1 or V7.5
  JMS classes, the performance of WebSphere MQ JMS may drop below
  that of the WebSphere MQ V6.0 JMS classes which are shipped with
  WebSphere Application Server V6.1.
  The additional overhead is due to the WebSphere MQ JMS
  classes executing trace routines, even when tracing has not
  been enabled in the WebSphere Application Server administrative
  console, or when the trace string is something like '*=info',
  which should not cause any WebSphere MQ JMS tracing.
  Thread dumps taken of the application server may show threads
  which are in WebSphere MQ methods making calls to a class called
  WAS6Tracer, for example:
  .
  Thread t@443: (state = BLOCKED)
  - java.util.Hashtable.get(java.lang.Object)
  - com.ibm.msg.client.commonservices.trace.Trace.traceable()
  - com.ibm.msg.client.commonservices.trace.Trace.
  methodEntryInternal(java.lang.Object.java.lang.String...)
  - com.ibm.msg.client.commonservices.trace.Trace.entry(..)
  - com.ibm.msg.client.wmq.factories.WAS6Tracer.traceData(...)
  - com.ibm.msg.client.commonservices.trace.Trace.
  traceDataInternal(int, java.lang.Object, ...)
  - com.ibm.msg.client.commonservices.trace.Trace.data(...)
  ...
  .
  Note that an analogous issue affecting the WebSphere MQ V7.0
  JMS classes was addressed by APAR IZ60251.
  

Local fix

• WebSphere MQ JMS tracing may be disabled entirely, eliminating
  the unwanted overhead, by opening the WebSphere Application
  Server V6.1 administrative console and navigating to
  "Application Server > $ServerName > Process Definition >
  Java Virtual Machine > Custom Properties", setting the property
  shown below, and restarting the application server:
  .
    com.ibm.msg.client.commonservices.trace.standalone=true
  .
  While this property is in effect, WebSphere MQ JMS tracing
  cannot be enabled through the WebSphere Application Server V6.1
  administrative console.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of WebSphere Application Server (WAS)
  V6.1 that configure the application server to use the WebSphere
  MQ (WMQ) V7.1 or V7.5 classes for Java Message Service (JMS) as
  their JMS
  provider.
  
  Platforms affected:
  All Distributed (iSeries, all Unix and Windows) +Java +Java zOS
  ****************************************************************
  PROBLEM SUMMARY:
  A logic error in the WebSphere MQ classes for JMS v7.1 and v7.5
  meant that the trace specification provided by WebSphere
  Application Server was not being
  correctly interpreted. This caused the WebSphere MQ classes for
  JMS to incorrectly enable tracing by default, regardless of the
  trace specification. This
  caused unnecessary performance and memory overheads when trace
  should not have been enabled.
  

Problem conclusion

• The WebSphere MQ V7.1 and V7.5 classes for JMS have been changed
  so that tracing is disabled rather than enabled by default.
  
  To enable tracing within a WebSphere Application Server V6.1
  environment, the trace string specified must include the trace
  group jmsApi.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following:
  
                     v7.1
  Platform           Fix Pack 7.1.0.4
  --------           --------------------
  Windows            7.1.0.4
  AIX                7.1.0.4
  HP-UX (Itanium)    7.1.0.4
  Solaris (SPARC)    7.1.0.4
  Solaris (x86-64)   7.1.0.4
  iSeries            7.1.0.4
  Linux (x86)        7.1.0.4
  Linux (x86-64)     7.1.0.4
  Linux (zSeries)    7.1.0.4
  Linux (Power)      7.1.0.4
  zOS                7.1.0.4
  
  Version            v7.5
  --------           --------------------
  Fix available in:  7.5.0.3
  
  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 SOL SPARC

• Fixed component ID

  5724H7223

Applicable component levels

• R710 PSY

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