PK62758: INCORROUT WHEN SELECT STATEMENT WITH GROUP BY UNDER PARALLELISM INVOLVES OUTER JOIN QUERY CONTAINING TABLE EXPRESSION

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Incorrout when SELECT statement with GROUP BY under //ism
  available. Reason is parallel outer join buffer doesn't adjust
  correctly .
  

Local fix

• Disable Parallelism, run Degree='1'.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 R810 and R910 parallelism users.     *
  ****************************************************************
  * PROBLEM DESCRIPTION: An INCORRECT OUTPUT may occur when      *
  *                      an OUTER JOIN query contains a TABLE    *
  *                      EXPRESSION and the column in the        *
  *                      selection list of the TABLE EXPRESSION  *
  *                      is selected out or used in the GROUP    *
  *                      BY clause running in parallel.          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  An INCORRECT OUTPUT may occur when an OUTER JOIN query contains
  a TABLE EXPRESSION and the column in the selection list of the
  TABLE EXPRESSION is selected out or used in the GROUP BY clause
  running in parallel. It is because such column buffer is not
  adjusted correctly under parallelism case.
  
  Following is an example of failing query:
  
  SELECT ...
    FROM      ...
         JOIN ...
           ON ...
         JOIN TABLE
              ( SELECT VSS.C1, ...
                  FROM VSS
                 WHERE VSS.C1 = VSA.C1
                   AND ...
                 GROUP BY VSS.C1
              ) AS VSST
           ON VSST.C1 = VSA.C1
         LEFT JOIN SOB1
           ON ...
         LEFT JOIN SIO2
           ON ...
        WHERE ...
        GROUP BY ..., VSST.C1, ...
  ;
  

Problem conclusion

• DB2 is modified to adjust the column buffer of the TABLE
  EXPRESSION in the OUTER JOIN query correctly under parallelism
  case.
  
  Additional Keyword: PARALLELISM SQLPARALLELISM SQLCPUP
                      SQLOUTERJOIN SQLTABLEEXPR SQLINCORR
                      INCORROUT
  

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:

  UK35668 UK35669

Modules/Macros

• DSNXOGRL DSNXOSR  DSNXOSRD DSNXOTC  DSNXOWIN
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• R810 PSY UK35668

     UP08/05/03 P F805

• R910 PSY UK35669

     UP08/05/03 P F805

Fix is available

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