PH67989: FAILURE TO CORRECTLY HANDLE A VERY UNLIKELY SYSTEM TIME RETRIEVAL ERROR LEADING TO INCORRECT UNLOADED DATA

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The Db2 HPU handling of an error in the system time retrieval
  process is incorrect. Instead of stopping the process, it
  proceeds further ignoring the returned value and considering a
  system time corresponding to a timestamp of
  0000-00-00-00:00:00.000000000000±00:00. This leads to a
  subsequent wrong evaluation of the CURRENT_DATE, CURRENT_TIME
  and CURRENT_TIMESTAMP SQL special registers. In such a case, any
  logical unload performed in native mode that uses at least one
  of the aforementioned registers in SQL expressions to define
  columns of the resulting table or as a predicate of a WHERE
  clause might produce incorrect data. The incorrectness of the
  unloaded data can consist in improperly filtered rows and/or in
  incorrect data for the output fields related to columns defined
  with SQL expressions using the incorrectly evaluated special
  registers.
  
  As a system time retrieval error is extremely unlikely, the
  wrong error handling and the related output incorrectness it
  leads to are almost impossible as well. It has never been
  reported to the IBM support.
  

Local fix

• No workaround is possible to address this extremely unlikely
  issue.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of Db2 High Performance Unload for     *
  *                 z/OS                                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: The Db2 HPU handling of an error in the *
  *                      system time retrieval process is        *
  *                      incorrect. Instead of stopping the      *
  *                      process, it proceeds further ignoring   *
  *                      the returned value and considering a    *
  *                      system time corresponding to a          *
  *                      timestamp of                            *
  *                      0000-00-00-00:00:00.000000000000±00:00. *
  *                      This leads to a subsequent wrong        *
  *                      evaluation of the CURRENT_DATE,         *
  *                      CURRENT_TIME and CURRENT_TIMESTAMP SQL  *
  *                      special registers. In such a case, any  *
  *                      logical unload performed in native mode *
  *                      that uses at least one of the           *
  *                      aforementioned registers in SQL         *
  *                      expressions to define columns of the    *
  *                      resulting table or as a predicate of a  *
  *                      WHERE clause might produce incorrect    *
  *                      data. The incorrectness of the unloaded *
  *                      data can consist in improperly filtered *
  *                      rows and/or in incorrect data for the   *
  *                      output fields related to columns        *
  *                      defined with SQL expressions using the  *
  *                      incorrectly evaluated special           *
  *                      registers.                              *
  *                                                              *
  *                      As a system time retrieval error is     *
  *                      extremely unlikely, the wrong error     *
  *                      handling and the related output         *
  *                      incorrectness it leads to are almost    *
  *                      impossible as well. It has never been   *
  *                      reported to the IBM support.            *
  *                                                              *
  *                      Local Fix: No workaround is possible    *
  *                      to address this extremely unlikely      *
  *                      issue.                                  *
  ****************************************************************
  * RECOMMENDATION: Apply the PTF                                *
  ****************************************************************
  Failure to correctly handle a very unlikely system time
  retrieval error leading to incorrect unloaded data
  

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:

• 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 UO05248

     UP25/10/18 P F510

• R610 PSY UO05249

     UP25/10/18 P F510

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.