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IT32195: IF THE ROW WIDTH PROCESSED BY A PARTIAL AGGREGATION OPERATOR IS MORE THEN 32K THEN WE COULD GENERATE INCORRECT RESULTS

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APAR status

  • Closed as program error.

Error description

  • IF THE ROW WIDTH GOING THROUGH A pGRPBY (PARTIAL AGGREGATION
    OPERATOR  ) IS MORE THEN 32K
    AND SORTHEAP IS SUFFICIENTLY LARGE
    THEN SOMETIMES Db2  COULD RETURN INCORRECT RESULTS  .
    
    example of plan:
    
           8.33333
           RETURN
            ( 1)
           84.626
             |
           8.33333
            GRPBY
            ( 2)
           84.6256
             |
           8.33333
            SCAN
            ( 3)
           84.5942
             |
           8.33333
            SORT
            ( 4)
           84.5938
             |
           8.33333
           pGRPBY       <<< if this lolepop has row of width > 32K
    and Sortheap is very large then sometimes wrong results could be
    returned.
            ( 5)
           84.5925
             |
    

Local fix

  • Disable partial aggregation by the following :   db2set
    DB2_REDUCED_OPTIMIZATION="NO_PEA,NO_PED"
    recycle the instance
    This is an internal registry variable setting to workaround this
    problem.
    The setting should be removed upon upgrade to the Fix pack level
    containing this fix :
    db2set DB2_REDUCED_OPTIMIZATION=
    recycle the instance
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * See Error Description and install fixpak with this fix.      *
    ****************************************************************
    

Problem conclusion

  • See Error Description and install fixpak with this fix.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT32195

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B50

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-03-16

  • Closed date

    2020-06-30

  • Last modified date

    2020-06-30

  • 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

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.5"}]

Document Information

Modified date:
01 July 2020