PM81785: READ-AHEAD

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Read-ahead improvements.
  *
  Additional keywords:
  QRep
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
  *                 Release 1.                                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: InfoSphere Data Replication, Q          *
  *                      Replication slows down when MQ transmit *
  *                      queue or Q Replication apply queue      *
  *                      exceed buffer pool capacity and size of *
  *                      MQ messages is greater than 30kB.       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  New read ahead function is provided to parallelize the disk read
  operations required to pre-stage data for large messages from
  the pageset into the bufferpool for MQGET operations.
  

Problem conclusion

• Users of Q Replication can enable the large message read ahead
  function for the queue managers hosting Q Replication
  transmission and apply queues with the MQSC commands:
   RECOVER QMGR(TUNE READAHEAD ON)
   RECOVER QMGR(TUNE RAHGET    ON)
  
  The function can be activated dynamically by entering at a
  console, or, added to the queue manager configuration by adding
  to a file processed in the CSQINP2 concatenation during queue
  manager start up.
  
  Additionally, non-serialized pageset access should be enabled
  by rebuilding ZPARM with an additional service switch activated
  and restarting queue manager. Contact IBM support for details
  on setting the Service parameter.
  100Y
  CSQIDUSE
  CSQIMGE9
  CSQIRAHP
  CSQIRECP
  CSQPMTRM
  CSQP1CON
  CSQP1DWP
  CSQP1INI
  CSQP1RAH
  

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:

  UK91439

Modules/Macros

• CSQIDUSE CSQIMGE9 CSQIRAHP CSQIRECP CSQPMTRM
  CSQP1CON CSQP1DWP CSQP1INI CSQP1RAH
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R100 PSY UK91439

     UP13/02/20 P F302

Fix is available

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