IC89609: PERFORMANCE DEGRADATION WHEN SEQUENCE IS PRESENT IN THE SELECT LIST COLUMN

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Under rare scenarios, performance degradation might be noticed
    if the following conditions are true:
    
    1. There is a sequence present in the output column of select
    list
    2. There are two or more views in the subselect directly below
    the sequence
    
    eg.
    select SEQUENCE1.NEXTVAL, col1, col2
    from view1 v1
    where v1.col1 =
       (select MAX(col1)
       from view1 v1
       where col2 = ?);
    

Local fix

  • Separate the sequence into a new subselect:
    
    select SEQUENCE1.NEXTVAL , col1, col2
    from
    (select *
    from view1 v1
    where v1.col1 =
       (select MAX(col1)
       from view1 v1
       where col2 = ?));
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All users on DB2 v97 FP8 and lower                           *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 V97 FP9                                       *
    ****************************************************************
    

Problem conclusion

  • First Fixed in DB2 V97 FP9
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC89609

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-01-17

  • Closed date

    2013-12-17

  • Last modified date

    2013-12-17

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

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

    IC89670 IC91783

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSY

       UP



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Document information


More support for:

DB2 for Linux, UNIX and Windows

Software version:

9.7

Reference #:

IC89609

Modified date:

2013-12-17

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