PI71809: MQ - PERFORMANCE IMPROVEMENT WHEN USING C CHANNEL EXITS.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Performance improvement of the CHIN when using C channel exits.
  

Local fix

• Add the SCEERUN library to the STEPLIB of the CHIN.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of IBM MQ for z/OS Version 9 Release 0             *
  * Modification 0.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Increased CPU cost when using exits written using the C      *
  * Systems Programming Environment and the CEEEV003 module from *
  * SCEERUN is in the LPA but not the Chinit STEPLIB.            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When an exit is written using the C Systems Programming
  Environment, each time it is invoked it LOADs the CEEEV003
  module. If this module is in the LPA (as is recommended by IBM),
  then the z/OS LOAD call can take considerably longer to locate
  the module. Since the module is also DELETEd after each
  invocation, the more expensive LOAD operation is repeatedly
  performed. This additional cost may significantly add to the
  overhead of invoking exits.
  

Problem conclusion

• Processing has been amended to pre-load the CEEEV003 module for
  each MQ dispatcher TCB at startup. This can result in a
  considerable improvement for LOAD times when using SPC exits
  when the CEEEV003 module is located in the LPA.
  

Temporary fix

Comments

APAR Information

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

  PI58641

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

  UI42996

Modules/Macros

• CSQXDISP
  

Fix information

• Fixed component name

  MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R000 PSY UI42996

     UP17/01/10 P F701

Fix is available

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