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LI73738: RUNNING A QUERY CONTAINING A PREDICATE USING A MAX/MIN AGGREGATEON A CONSTANT MAY CRASH THE INSTANCE

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • A query containing a predicate on the output of a MAX or MIN
    function applied on a constant may crash the DB2 instance with a
    SIGSEGV.
    
    An example scenario for such an abend to occur follows:
    
    CREATE TABLE T1 (C1 INT);
    SELECT  MAX_COL
    FROM    (SELECT MAX(1) AS MAX_COL
             FROM   T1
             GROUP  BY C1
            ) AS T
    WHERE   MAX_COL = 1;
    
    The stack trace may look something like:
    
    pp__17sqlnq_exphxpchildFv
    address: 0xnnnnnnnnnnnnnnnn
    sqlnr_gb_ppdto_action__FP10sqlnr_qrwaPiP14sqlnr_progress
    sqlnr_comp__FPiiP16sqlnr_rule_stateP10sqlnr_qrwaP14sqlnr_progres
    s
    sqlnr_seq__FPiP10sqlnr_qrwaP14sqlnr_progressP12sqlnr_rclass
    sqlnr_rcc__FiP10sqlnr_qrwaPiP14sqlnr_progress
    ...
    

Local fix

  • As a workaround to avoid the crash, remove any MAX/MIN
    aggregations on constants, i.e., the above query can be
    semantically equivalently rewritten as:
    
    SELECT  MAX_COL
    FROM    (SELECT 1 AS MAX_COL
             FROM   T1
             GROUP  BY C1
            ) AS T
    WHERE   MAX_COL = 1;
    

Problem summary

  • USERS AFFECTED:  ALL
    
    PROBLEM DESCRIPTION:  Please refer to ERROR DESCRIPTION.
    
    PROBLEM SUMMARY:  Please refer to ERROR DESCRIPTION.
    

Problem conclusion

  • Problem was first fixed in version 9.5 Fix Pack 3.
    

Temporary fix

  • Please refer to the LOCAL FIX.
    

Comments

APAR Information

  • APAR number

    LI73738

  • 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

    2008-09-02

  • Closed date

    2009-04-24

  • Last modified date

    2009-04-24

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

    LI73736

  • 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

  • R810 PSN

       UP

  • R820 PSN

       UP

  • R910 PSN

       UP

  • R950 PSN

       UP

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Document Information

Modified date:
24 April 2009