PK66947: SELECT COUNT(*) GIVES NO RESULT WHEN CURRENT DEGREE = 'ANY' INVOLVING IS NULL PREDICATE THAT IS ALSO INDEX PARTITION KEY

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Incorrout  no rows NRF for the following
  select: SET CURRENT DEGREE = 'ANY'; SELECT COUNT(*)  FROM
  DB111.TABLE_1 A WHERE A.COLX  IS NULL WITH UR ;
  INVOLVING IS NULL PREDICATE THAT IS ALSO INDEX PARTITION KEY
  on a Parallel Group.
  .
  L2 Diagnostic Key:  ISNULL  PGD  LPT
  .
  

Local fix

• Disabling parallelism can bypass the problem.
  Set Current Degree='1' or Bind with Degree='1'.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 for z/OS users with PARALELLISM      *
  *                 enabled, and sql that contains an IS NULL    *
  *                 predicate.                                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: DB2 may return an incorrect value for   *
  *                      a table accessed in parallel using an   *
  *                      index with a matching key covered by    *
  *                      an IS NULL predicate.  Also, the key    *
  *                      column must be a VARCHAR type.          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Example of an SQL and index when accessed using PARALLELISM
  may result in an incorrect output:
  
  CREATE Index1 on Table1(VarcharColumn)
  
  SELECT VarcharColumn
  From Table1
  Where VarcharColumn IS NULL;
  
  where VarcharColumn is a VARCHAR type.
  

Problem conclusion

• With the fix, DB2 now correctly processes a 'col IS NULL'
  predicate when the col is a key of an index that is used to
  partition a table for parallel access.
  
  ADDITIONAL KEYWORDS: SQLSUM SQLISNULL SQLCPUP SQLIOP SYSPLEX
  SQLSYSPLEXP PARALLELISM SQLPARALLELISM SQLINCORR SQLINCORROUT
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UK39278 UK39279

Modules/Macros

• DSNXOLFQ
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• R810 PSY UK39278

     UP08/09/10 P F809

• R910 PSY UK39279

     UP08/09/10 P F809

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.