IT33901: Performance degradation when using extended message selection

APAR status

• Closed as program error.

Error description

• When using extended message selection the users might observe
  message processing degradation and
  the following failure data capture (FDC) records indicating
  delays in acquiring and releasing RWMutex would be generated.
  
  2020/07/07 01:31:54.302258+8 amqzlaa0 109858 1357 XC514090
  xlsRWMutexRequest xecL_W_LONG_LOCK_WAIT
  2020/07/07 01:31:55.310997+8 amqzlaa0 104638 3620 XC514090
  xlsRWMutexRequest xecL_W_LONG_LOCK_WAIT
  2020/07/07 01:32:08.412973+8 amqzlaa0 104638 3639 XC515091
  xlsRWMutexRelease xecL_W_LONG_LOCK_WAIT
  2020/07/07 01:32:08.691239+8 amqzlaa0 109706 2984 XC515091
  xlsRWMutexRelease xecL_W_LONG_LOCK_WAIT
  

Local fix

• Restart the queue manager
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users using extended message selection with intermittent delays
  in MQ or broker processing the messages.
  One of the major reasons for delays could be high I/O
  latency(e.g. 30 seconds).
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  MQ encountered message processing delays due to high I/O latency
  which also affected extended message selection(content
  filtering) performance. When the I/O latency improved MQ could
  not recover from the initial performance degradation and
  continue to process the message slowly.  The current logic in
  extended message selection did not account for the initial
  slowness and this caused problem in recovery.
  

Problem conclusion

• MQ code has been modified to recover from the initial slowness
  in message processing when using extended message selection.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.16
  v9.0 LTS   9.0.0.12
  v9.1 LTS   9.1.0.8
  v9.2 LTS   9.2.0.2
  v9.x CD    9.2.2
  
  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 is sysrouted FROM one or more of the following:

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

  IT37228

Fix information

• Fixed component name

  IBM MQ BASE MP

• Fixed component ID

  5724H7271

Applicable component levels