IT12383: ENABLING REOPT ALWAYS VIA OPTIMIZATION GUIDELINE MAY LEAD TO INCORRECT RESULTS AS PARAMETER VALUES MAY BE RE-USED INCORRECTLY

DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• Incorrect result may be returned if REOPT ALWAYS is enabled
  through an optimization guideline as parameter values from
  previous
  execution of the same statement  may be incorrectly re-used.
  
  REOPT ONCE and REOPT NONE settings are not affected.
  
  Note that optimization guidelines may be specified for an SQL
  statement either:
  - within the statement text via an embedded optimization
  guideline
  - or via an optimization profile.
  In either case, incorrect results can result.
  
  Example of enabling REOPT ALWAYS via optimization
  guideline that can cause incorrect results:
  /*<OPTGUIDELINES> <REOPT VALUE="ALWAYS"/> </OPTGUIDELINES>*/
  

Local fix

• Use REOPT ONCE if REOPT needs to be enabled via optimization
  profile, otherwise, use other ways to enable REOPT ALWAYS
  (e.g. REOPT BIND option)
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * ALL                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to DB2 10.1 Fix Pack 6                               *
  ****************************************************************
  

Problem conclusion

• First fixed in DB2 10.1 Fix Pack 6
  

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:

  IT15023 IT15043 IT20366

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RA10 PSN UP

     FIX