PH71573: UNPREDICTABLE AND INTERMITTENT ABEND DURING AN UNLOAD USING BSAM METHOD

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An unload terminates in abend if all the following conditions
  are fulfilled :
  - zIIP usage is active
  - at least one of the following conditions is true :
     - the data are ulnoaded to a sequential dataset and the BSAM
       method is used for OUTPUT datasets (as reported by the
       INZ666I message)
     - (in HPU 6,1 only) a dataset is alloacted for the INDEXSCAN
      feature (as reported by the INZX111 message) is used to
      process the unload and the BSAM method is used for the
      INDEXSCAN datasets (as reported by the INZ666I message)
  - a very precise timing condition between Db2 HPU internal
    threads is fulfilled
  
  The required timing condition makes this issue very rare and
  intermittent.
  

Local fix

• A new run of the failing unload can terminate successfully but
  the issue may be completely avoided by request the QSAM method
  for the concerned type of dataset (OUTPUT or INDEXSCAN). For
  example, specify IO_SEQ_METHOD OUTPUT(QSAM),INDEXSCAN(QSAM) in
  the GLOBAL option block.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of Db2 High Performance Unload for     *
  *                 z/OS                                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: An unload terminates in abend if all    *
  *                      the following conditions are            *
  *                      fulfilled :                             *
  *                      - zIIP usage is active                  *
  *                      - at least one of the following         *
  *                        conditions is true :                  *
  *                         - the data are unloaded to a         *
  *                           sequential dataset and the BSAM    *
  *                           method is used for OUTPUT datasets *
  *                           (as reported by the INZ666I        *
  *                           message)                           *
  *                         - (in HPU 6,1 only) a dataset is     *
  *                           allocated for the INDEXSCAN        *
  *                           feature (as reported by the        *
  *                           INZX111 message) is used to        *
  *                           process the unload and the BSAM    *
  *                           method is used for the INDEXSCAN   *
  *                           datasets (as reported by the       *
  *                           INZ666I message)                   *
  *                      - a very precise timing condition       *
  *                        between Db2 HPU internal threads is   *
  *                        fulfilled                             *
  *                                                              *
  *                      The required timing condition makes     *
  *                      this issue very rare and intermittent.  *
  *                                                              *
  *                      Local fix: A new run of the failing     *
  *                      unload can terminate successfully but   *
  *                      the issue may be completely avoided by  *
  *                      request the QSAM method for the         *
  *                      concerned type of dataset (OUTPUT or    *
  *                      INDEXSCAN). For example, specify        *
  *                      IO_SEQ_METHOD OUTPUT(QSAM),             *
  *                      INDEXSCAN(QSAM) in the GLOBAL option    *
  *                      block.                                  *
  ****************************************************************
  * RECOMMENDATION: Apply the PTF                                *
  ****************************************************************
  Unpredictable and intermittent ABEND during an unload using BSAM
  method
  

Problem conclusion

• Code has been changed to fix this problem
  

Temporary fix

Comments

APAR Information

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

  PH71572

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

Modules/Macros

• INZUTILK
  

Fix information

• Fixed component name

  DB2 HI PERF UNL

• Fixed component ID

  5697F4400

Applicable component levels

• R520 PSY UO08456

     UP26/07/02 I 1000

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.