PM15484: DFHNQ0002 X'0212' FOR EXTENDED, RECOVERABLE ESDS FILES

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• CICS emergency restart fails with:
  DFHNQ0002 A severe error (code X'0212') has occurred in module
            DFHNQNQ
  DFHRM0002 A severe error (code X'069A') has occurred in module
            DFHRMR1D.
  .
  Two tasks are writing to an extended, recoverable ESDS file.
  Task1 has completed it's file WRITE and a corresponding
  WRITE_ADD and WRITE_ADD_COMPLETE have both been logged. Task2
  has logged it's WRITE_ADD to the same file but CICS abended
  before the record was written to VSAM, and so before the
  WRITE_ADD_COMPLETE was logged.
  .
  On the subsequent emergency restart, DFHFCIR correctly
  reacquires the FCDSESWR write lock for task2 because there was
  no WRITE_ADD_COMPLETE record on the system log. DFHFCIR then
  encounters the WRITE_ADD_COMPLETE record for task1, but does not
  set flag FLAB_WA_COMPLETE_SEEN. So when DFHFCIR encounters the
  WRITE_ADD record, it doesn't remember it, and assumes a WRITE
  request must have been incomplete and attempts to acquire the
  FCDSESWR write lock. This causes a locked error and message
  DFHNQ0002 0212 is issued. Trace shows:
  .
  NQ 0212 NQNQ  *EXC* - Enqueue_locked_error -
                        FUNCTION(REACQUIRE_ENQUEUE)
  .
  This problem occurs because DFHFCIR incorrectly ignores the
  WRITE_ADD_COMPLETE record for an extended ESDS file.
  .
  Additional Symptom(s) Search Keyword(s):
  KIXREVEAA 212 0212 FCDSRECD NQ0002 RM0002
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: A CICS system experienced an outage,    *
  *                      and was restarted using EMERGENCY       *
  *                      restart. During this restart CICS       *
  *                      encountered message DFHNQ0002 A severe  *
  *                      error (code X'0212') has occurred in    *
  *                      module DFHNQNQ.                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A CICS system experienced an outage. At the time of the outage
  there had been two inflight tasks both writing to the same
  Extended Addressing ESDS file. CICS was then restarted using
  EMERGENCY restart. During this restart CICS read the File
  Control journal entries in DFHLOG, and tried to back out these
  two tasks. CICS then encountered message
    DFHNQ0002 A severe error has occurred (code X'0212')
    in module DFHNQNQ,
  followed by
    DFHRM0002 A severe error has occurred (code X'069A')
    in module DFHRMR1D.
  Trace point
    NQ 0212 *EXC* Enqueue_locked_error
  was also issued, and CICS shut down.
  .
  When writing to an Extended Addressing ESDS CICS first writes an
  83 (write-add) record to DFHLOG, then calls VSAM to perform the
  write. It is only at this point that the location the record is
  written to is confirmed. When VSAM completes the write it
  returns to CICS the RBA used, and CICS writes an 84
  (write-add-complete) record to DFHLOG which should contain
  this RBA. These records are then used to perform backout.
  .
  The problem here was twofold; the primary problem was that the
  84 records were not being processed by CICS during the emergency
  restart. This led to a situation where both tasks attempted to
  get the ESDS file write lock (FCDSESWR), leading to a conflict
  and giving rise to the NQ0002 error. In addition
  the RBA information (stored in field fljb_cd_key) was
  missing from the 84 record.
  
  Additional Keywords: msgDFHNQ0002 msgDFHRM0002
  

Problem conclusion

• DFHFCIR has been altered so that the 84 log records are read in
  and processed correctly. DFHFCLJ has also been altered so that
  the actual RBA used by VSAM to perform the write, for an
  extended ESDS, is written out to the 84 record in field
  fljb_cd_key. Field fljb_cd_key_length in the record has also be
  corrected such that it now contains the length of the key.
  These two changes together allow backout to proceed correctly,
  since the 84 log record now contains the required information,
  and is being processed.
  

Temporary fix

•             *********
              * HIPER *
              *********
  FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

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

  PM16633 UK59279

Modules/Macros

•    DESFCIR  DESFCLJ  DFHFCIR  DFHFCLJ  DFHFCLJA
  DFHFCLJM DFHFCLJT
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R500 PSY UK59279

     UP10/08/05 P F008

Fix is available

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