PM74825: WMQ FOR Z/OS V7.1 : BROWSE WITH MARK FUNCTIONALITY NOT WORKING CORRECTLY WITH SHARED QUEUES. BROWSE MARKS ARE BEING LOST.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Customer was using multiple programs to browse messages on a
  shared queue and found that after issuing the first browse with
  options MQGMO-BROWSE-FIRST MQGMO-UNMARKED-BROWSE-MSG
  MQGMO-MARK-BROWSE-CO-OP that a subsequent browse
  returned the same message.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ Version 7          *
  *                 Release 1 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Application browsing messages from a    *
  *                      shared queue using the following        *
  *                      options:                                *
  *                      MQGMO_MARK_BROWSE_CO_OP                 *
  *                      MQGMO_BROWSE_FIRST                      *
  *                      MQGMO_UNMARKED_BROWSE_MSG               *
  *                      and the queue manager attribute         *
  *                      MARKINT(NOLIMIT) can browse messages    *
  *                      more than once.                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  There is a timing window in the get browse process in CSQEMGEB
  and in CSQEMGEK when an unmarked message is marked
  in the coupling facility structure and in the message token
  structure in memory.
  
  During this window, CSQEMTIN (time driven process) can find the
  mark in the CF but not in memory and decides to clear the mark
  in the CF (assuming that a getter thread has died) making the
  message available for browsing again.
  

Problem conclusion

• An inprogress count is incremented when the message is selected
  as unmarked before the CF is updated and it is decremented when
  the coop mark has been set in both the CF and in memory.
  CSQEMTIN checks if the inprogress count before deciding to clear
  (expire) any coop mark.
  100Y
  CSQEMGEB
  CSQEMGEK
  CSQEMTIN
  CSQMMTIN
  CSQMMTPR
  

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:

  UK91224

Modules/Macros

• CSQEMGEB CSQEMGEK CSQEMTIN CSQMMTIN CSQMMTPR
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R100 PSY UK91224

     UP13/02/20 P F302

Fix is available

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