IT25187: UDF FUNCTIONS RUN AGAINST COLUMNAR (BLU) TABLES MIGHT RETURN INCORRECT RESULTS

Db2 Version 11.1 Mod4 Fix Pack4 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 4 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 5 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 7 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• UDF functions run against columnar tables, that are pushed down
  to the columnar engine (i.e. below CTQ in the explain), might
  return incorrect result under rare timing conditions. One of the
  built-in functions that is confirmed to be affected is
  DBMS_UTILITY.GET_HASH_VALUE.
  Problem is specific to Db2 release 11.1 Mod 3 Fix Pack 3.
  

Local fix

• this internal registry setting will turn off performance
  optimization done in v11 fp3 which is triggering the issue:
  db2set DB2_CDE_FLAGS=288230376151711744
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * ALL                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Db2 11.1 Mod 4 Fixpack 4 or higher                *
  ****************************************************************
  

Problem conclusion

• First fixed in Db2 11.1 Mod 4 Fixpack 4
  

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:

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSN

     UP