PI78154: MQ Z/OS: SET SYSTEM EXCLMSG(X...) DOES NOT SUPPRESS CHIN MESSAGES IF THE COMMAND IS IN CSQINP2 JUST AFTER START CHINIT

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• There is a timing window where issuing SET SYSTEM EXCLMSG(X...)
  just after the CHIN has started results in the messages not
  being excluded.
  
  For instance, if you have
    START CHINIT
    SET SYSTEM EXCLMSG(X511,X512)
  in a CSQINP2 member, messages CSQX511I and CSQX512I still
  appear in the CHIN joblog.
  
  With the reverse order
    SET SYSTEM EXCLMSG(X511,X512)
    START CHINIT
  the messages are suppressed.
  
  If the SET SYSTEM command is issued once the channel initiator
  is already up, the messages are correctly excluded.
  

Local fix

• When SET SYSTEM EXCLMSG(X...) and START CHINIT are in the same
  CQINP2 member, put the SET SYSTEM EXCLMSG command first.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of IBM MQ for z/OS Version 9 Release 0             *
  * Modification 0.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Changes to EXCLMSG using SET SYSTEM are ignored by the       *
  * channel initiator when the SET SYSTEM command follows START  *
  * CHINIT in CSQINP2.                                           *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * None                                                         *
  ****************************************************************
  During START CHINIT processing, CSQMSCHI builds the XPAR, which
  includes the current list of excluded messages. When the chinit
  starts, this XPAR is copied to the chinit address space.
  When the subsequent SET SYSTEM command is run, it updates the
  XPAR in the queue manager address space and attempts to copy the
  updated version to the chinit address space. However when
  running during CSQINP2 processing, the ALET for accessing the
  chinit has not yet been created and so the copy fails, and so
  the updates are ignored.
  

Problem conclusion

• Chinit startup processing is changed to detect when START CHINIT
  has been issued from CSQINP2, and to delay chinit startup until
  CSQINP2 processing has completed, allowing any subsequent SET
  SYSTEM commands to complete prior to the initial copy of the
  XPAR being copied to the chinit address space.
  

Temporary fix

Comments

APAR Information

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

  PI72378

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

  UI46014

Modules/Macros

• CSQJC00B CSQMQMUP CSQMSCHI CSQXGRIM
  

Fix information

• Fixed component name

  MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R000 PSY UI46014

     UP17/05/19 P F705

Fix is available

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