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IT28739: WRONG RESULTS MIGHT BE OBSERVED WHEN RUNNING QUERIES WITH OUTER JOINS AND GROUP BY OPERATIONS

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APAR status

  • Closed as program error.

Error description

  • A query might generate wrong results when the query contains the
    following characteristics:
    1) it contains at least one outer join
    2) on the null producing side of this outer join, there is at
    least one aggregation and this null producing side at most
    produces one row
    3) the row preserving side of this outer join also at most
    produces one row
    
    Ex.
    select A.a1, B.sum
    from a
    A              -- row preserving side
    left join
    (select sum(B.b3) as sum from b B where B.b1=1 and B.b2=2) B  --
    null producing side
    on 1=1
    where A.a1=1
    
    Where A.a1 contains unique key so the predicate - "A.a1=1"
    ensures that there is at
    most one row output from A, and the row preserving side also
    only outputs at most one row due to the aggregation.
    

Local fix

  • db2set -im DB2COMPOPT=NO_GBPU
    

Problem summary

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

Problem conclusion

  • See Error Description and install the fix.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT28739

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-04-10

  • Closed date

    2019-11-29

  • Last modified date

    2020-03-23

  • 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 PSY

       UP

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
04 May 2022