PI64965: REGION HANGS AS THE QR TCB DOES NOT SEEM TO BE RUNNING AND CSA TIME HAS NOT BEEN UPDATED.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• CICS region is hung. Review of the dump shows that the QR TCB
  is not running. The CSA time is behind the time of the dump.
  The QR TCB is hung because DB2 PAUSEd the TCB. However, CICS
  should not be making a DB2 call from the QR TCB.
  Looking at the trace further, I see the following:
  1. Task enters D2D2 to do a DB2_API_CALL on an L8 tcb and
  attempts to associate to an existing protected thread. While
  this call is in DB2, TMON purged the task. The task then gets
  dispatched on the QR TCb to do some recovery and issues an
  exception trace entry:
  AP 3259 D2D2 *EXC* - FAILED_TO_ASSOCIATE
  followed by the D2D2 recovery routine being driven. D2D2
  returns with a RESPONSE(EXCEPTION)
  REASO(ASSOCIATE_FAILED_FOR_PTHD).
  The very next trace entry shows this task going back into D2D2
  under the QR TCB. The retry logic was added by PI23186/PI27467
  but it is wrong to be retrying on the QR TCB!
  Additional Symptom(s) Search Keyword(s): KIXREVDWZ
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All CICS users.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * CICS hangs whilst executing a DB2 task                       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * .                                                            *
  ****************************************************************
  A change in base code allowed DFHD2D2 to recover more
  efficiently when attempting to reuse a protected DB2 CSUB thread
  which had been previously purged. The fix ensured that DFHD2D2
  would return a response to DFHD2EX1 which resulted in DFHD2D2
  being redriven and attempting the associate again to a new
  thread rather than abending.  In this case however, the CICS
  task was forcepurged whilst the TCB was still in DB2 and as a
  result the L8 TCB was destroyed, causing the redrive of DFHD2D2
  to be executed under the QR TCB.
  

Problem conclusion

• DFHD2D2 has been changed so that, if the redrive is issued
  whilst executing on the QR TCB we abend with a disaster response
  rather than attempt the re-associate.
  

Temporary fix

Comments

APAR Information

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

  PI61825

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

  UI40554

Modules/Macros

• DFHD2D2
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R000 PSY UI40554

     UP16/09/21 P F609

Fix is available

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