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LI73549: MDC ROLLOUT DOES NOT HAPPEN DURING DELETE OPERATION IN CERTAIN SITUATIONS

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APAR status

  • Closed as program error.

Error description

  • When a table has the MDC block index created against a column,
    it gets used during the select operation.  However on certain
    situations the MDC block index does not get used and uses a
    regular index, causing the delete operation to take a long time.
    
    The optimizer is picking the regular index rather than the MDC
    index based on the lower cost upto that point. It is not aware
    of the MDC roll out presence and hence chooses the inefficient
    index for delete.
    

Local fix

Problem summary

  • MDC ROLLOUT DOES NOT HAPPEN DURING DELETE OPERATION IN CERTAIN
    SITUATIONS
    ERROR DESCRIPTION:
    When a table has the MDC block index created against a column,
    it gets used during the select operation.  However on certain
    situations the MDC block index does not get used and uses a
    regular index, causing the delete operation to take a long time.
    
    The optimizer is picking the regular index rather than the MDC
    index based on the lower cost upto that point. It is not aware
    of the MDC roll out presence and hence chooses the inefficient
    index for delete.
    
    USERS AFFECTED:  All
    

Problem conclusion

  • First fixed in v9.5 fp2.
    

Temporary fix

Comments

APAR Information

  • APAR number

    LI73549

  • Reported component name

    DB2 UDE ESE LIN

  • Reported component ID

    5765F4104

  • Reported release

    950

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-06-27

  • Closed date

    2009-03-24

  • Last modified date

    2009-03-24

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

    LI73077

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

Fix information

  • Fixed component name

    DB2 UDE ESE LIN

  • Fixed component ID

    5765F4104

Applicable component levels

  • R950 PSY

       UP

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Document Information

Modified date:
24 March 2009