PK77375: IMS SHUTDOWN MAY HANG WHEN USING /CHECKPOINT PURGE COMMAND.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• It is possible for a hang to occur during /CHE PURGE shutdown
  processing if a message is placed on the queue for a class with
  no active MPP region to process the class during the shutdown
  process. In this case, a dump will show transactions on the
  queue (CLASS 4 in this case), and one or more MPP regions
  waiting on SUBQ3 (MPP regions process CLASS 10 in this case).
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All IMS V10 users of /CHE PURGE command      *
  ****************************************************************
  * PROBLEM DESCRIPTION: IMS Shutdown hang after issuing /CHE    *
  *                      PURGE command                           *
  ****************************************************************
  * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
  ****************************************************************
  IMS shutdown can hang after issuing the /CHE PURGE command if
  there are dependent regions active, but none of the active
  dependent regions process the transaction class(es) for which
  there are eligible transactions for scheduling.
  
  This problem is caused by a timing hole between the /CHE PURGE
  logic in the shutdown module DFSTRM00 and the MPP/JMP purge
  subroutines in DFSSMSC0/DFSSJMP0 (subroutines SMSC5000 and
  SJMP5000 respectively) .
  
  DFSTRM00 will first post all regions. Any regions waiting will
  wake-up and perform PURGE processing if no work was found for
  that region.  If the dependent region is able to complete PURGE
  processing before DFSTRM00 continues (after posting all
  dependent regions) and marks the transaction class tables (TCTs)
  inactive, then the dependent region(s) can potentially WAIT on
  the scheduler subqueue, never to be posted.  Thus, the shutdown
  hang.
  
  Additional Keywords:
  CMDCHE CMDCHEPUR CMDCHEPURGE CHE PUR
  

Problem conclusion

• GEN:
  KEYWORDS:
  
  *** END IMS KEYWORDS ***
  DFSSMSC0:
  DFSSJMP0:
  Logic has been added to the PURGE subroutine (SMSC5000/SJMP5000)
  to set the SAPSSTOP bit for the region performing PURGE
  processing if there are no transactions eligible for scheduling
  in the dependent region currently performing PURGE processing.
  

Temporary fix

Comments

APAR Information

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

  PK76755

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

  UK44231

Modules/Macros

• DFSSJMP0 DFSSMSC0
  

Fix information

• Fixed component name

  IMS V10

• Fixed component ID

  5635A0100

Applicable component levels

• R010 PSY UK44231

     UP09/02/27 P F902

Fix is available

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