PM54955: INCORROUT (LESS ROW FOUND) ON QUERY WITH CORRELATED SUBQUERY WITH PARALLELISM

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Incorrout (less row found) when running a query which contains
  correlated subquery with parallelism.
  
  Additional Keywords: SQLINCORR SQLINCORROUT DB2INCORR/K
             SQLSUBQUERY SQLCORRSUBQ
  

Local fix

• SET DEGREE(1) to disable parallelism.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 810 , DB2 9 and DB2 10 for z/OS      *
  *                 users of parallelism.                        *
  ****************************************************************
  * PROBLEM DESCRIPTION: Incorrect output could occur when a     *
  *                      query contains scalar fullselect in its *
  *                      predicate running in parallel.          *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Incorrect output could occur when a query contains scalar
  fullselect in its predicate running in parallel.
  
  The following query could recreate the problem:
  
  CREATE TABLE TT1(C1 INTEGER, C2 VARCHAR(10), C3 SMALLINT);
  CREATE TABLE TT2(C1 INTEGER, C2 VARCHAR(10), C3 SMALLINT);
  
  SELECT A.C1,B.C2
  FROM TT1 A, TT2 B
  WHERE A.C1 >100 AND
        (SELECT MAX(C.C3) FROM TT1 C
         WHERE C.C2 = A.C2)
        =
        (SELECT MAX(D.C3) FROM TT2 D
         WHERE D.C2 = B.C2);
  The above SQL statement could return incorrect output.
  

Problem conclusion

• DB2 is updated to handle the scalar fullselect in  predicate
  correctly to make it return correct result when running in
  parallel.
  Additional keywords: SQLSCALAR SQLFULLSELECT SQLPARALLELISM
                       SQLINCORR INCORROUT SQLINCORROUT
                       DB2INCORR/K
  

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:

  UK76315 UK76351 UK76358

Modules/Macros

• DSNXOEXC
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UK76315

     UP12/03/08 P F203 ½

• R810 PSY UK76351

     UP12/03/08 P F203 ½

• R910 PSY UK76358

     UP12/03/08 P F203 ½

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.