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IT21403: FLOATING POINT TO DECIMAL CONVERSION IN ORA MODE CAN RESULT IN LESS ACCURATE RESULTS FOR NUMBERS WITH LARGE SCALE

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • This APAR is done as a temporary internal workaround
    for a specific customer. This APAR is not a problem and can be
    ignored by any users.
    
    As per IEEE 754 standard for floating point datatypes, floating
    point numbers are a binary approximation of an actual number.
    As such, when these datatypes are stored, there is potential for
    a loss of accuracy. For some numbers, in particular
    (but not limited to) those numbers that have a large amount of
    scale digits, this gives a number that may lose the
    precision and accuracy that is needed in some applications.
    
    In DB2, the floating point datatypes are DOUBLE, FLOAT, and REAL
    (see documentation about DB2 datatypes). If having precision and
    accuracy is required for the application, then it is not
    recommended to use floating point types, and the DECIMAL or
    DECFLOAT datatype should be used instead.
    
    This APAR provides an alternate approach from float to decimal
    for some numbers that are suffering from the
    binary approximation accuracy concerns.
    
    Since this is a behaviour change in how floating point numbers
    are treated by DB2, this change is not provided for general use.
     If this APAR is required, then please contact DB2 support team,
    who can provide guidance on how to enable this alternate mode
    for converting floating point types to DECIMAL.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to Db2 11.1 Mod 3 Fix Pack 3 or higher               *
    ****************************************************************
    

Problem conclusion

  • First fixed in Db2 11.1 Mod 3 Fix Pack 3
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT21403

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    B10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-07-12

  • Closed date

    2018-03-19

  • Last modified date

    2018-03-19

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

    IC96938

  • 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 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: B10

Reference #: IT21403

Modified date: 19 March 2018