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IT04236: SQL STATEMENT WITH REPARTITIONED JOINS MIGHT RETURN INCORRECT RESULTS IN A DPF SYSTEM

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • A complex SQL statement, requiring repartitioned joins in a DPF
    system, might produce wrong results if the following conditions
    are met:
    
    - The SQL statement includes two or more joins that are not
    collocated
    - At least one of the joins chosen by the optimizer is a
    repartitioned join, identifiable by the presence of a TQ
    operator somewhere below both inputs to the join
    - The join columns are of short-string type (CHAR, VARCHAR) with
    differing lengths.
    
    Note that the presence of these conditions does not always lead
    to incorrect results.
    

Local fix

  • You can attempt to avoid the repartition join by creating one or
    more materialized query tables (MQT) on each table referenced in
    the join, where the MQT is defined with a hash distribution key
    on the join columns.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * Database partitioning feature                                *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 version 10.1.0.5.                             *
    ****************************************************************
    

Problem conclusion

  • The problem was first fixed in DB2 version 10.1.0.5.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT04236

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-09-05

  • Closed date

    2015-07-10

  • Last modified date

    2015-07-10

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

    IT04226

  • 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

  • RA10 PSN

       UP

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
10 July 2015