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IC98349: A QUERY WITH AN OR PREDICATE MIGHT RETURN INCORRECT RESULTS

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • A query might return incorrect results when the query has the
    following pattern:
    1. The query contains a subquery block, called subQ1, that
    references a base table BT1, called that quantifier Q1, and
    another subquery, called subQ2
    2. The subQ2 block references the same base table BT1. Call that
    quantifier Q2.
    3. The subQ2 block has an OR predicate, called orPrd, qualifying
    all the following conditions:
    3.a. The orPrd predicate takes the form (orPrd1 OR orPrd2 [OR
    ...]).  One example could be an orPD predicate with at least two
    OR subterms denoted as orPrd1 and orPrd2.
    3.b. The orPrd predicate references column colX from Q1, and
    orPrd2 references column colX from Q2. In other words, orPrd1 is
    a correlation predicate, orPrd2 is local predicate, and their
    referenced columns derive from the same base table column.
    3.c. The orPrd1 and orPrd2 predicates are exactly matched or
    subsume each other. For example, Q1.colX=1 and Q2.colX = 1 are
    exactly matched, Q1.colX in (1,2) is subsumed by Q2.colX in
    (1,2,3).
    4. The query is compiled at optimization level 5 or above.
    
    The symptom is in the optimized statement when after either the
    orPrd1 or orPrd2 predicates are removed.
    

Local fix

  • Reduce the query optimization level to below 5.  For example,
    issue the "db2 set current query optimization 2" command to
    reduce optimization level to 2.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All users                                                    *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 version 10.1.0.4.                             *
    ****************************************************************
    

Problem conclusion

  • The problem is first fixed in DB2 version 10.1.0.4.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC98349

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-12-16

  • Closed date

    2014-05-08

  • Last modified date

    2014-05-26

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

    IC98331

  • 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

  • RA10 PSN

       UP

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.1","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
26 May 2014