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IC82902: IMPROVE PARSING ROBUSTNESS FOR OPTIMIZER GUIDELINES

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • Customers that are using optimizer guidelines - to force a
    specific query plan - sometimes have observed performance issue
    that are caused by a sub optimal access plan. The problem
    typically occurs intermittently and can be fixed by
    "re-optimizing" the query.
    
    A closer investigation will reveal that the DB2 optimizer might
    fail to correctly apply the optimizer guideline with an SQL437W
    RC=13.
    The best way to verify that you have encountered this APAR is to
    get an "explain from section" of the compiled query and to
    verify the access plan if the desired optimizer guideline was
    applied or not.
    
    This issue is caused by an incorrect parsing of the XML tag that
    is used for optimizer guideline. With this APAR we will correct
    these problems.
    

Local fix

  • Submit the query again and ensure it get recompiled/reoptimized
    so that a new section will end up in the package cache.
    One method to accomplish this would be the "FLUSH PACKAGE CACHE
    DYNAMIC ..." statement.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Problem Description above.                               *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 9.7 Fix Pack 7.                       *
    ****************************************************************
    

Problem conclusion

  • First fixed in Version 9.7 Fix Pack 7.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC82902

  • 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

    2012-04-25

  • Closed date

    2012-10-25

  • Last modified date

    2012-10-25

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

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

    IC87286

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP

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Document Information

Modified date:
25 October 2012