PM75619: INCORRECT OUTPUT WHEN IOE AND MULTIPLE CCSID EXIST FOR A QUERY: SENSITIVITY TO CLUSTERING NOT DETECTED SO NO SUGGESTION TO REORG

A fix is available

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APAR status

  • Closed as program error.

Error description

  • 1) Incorrect output can occur for a query where
    Index-on-expression (IOE) is used and multiple CCSIDs exist;
    2) Sensitivity to clustering is not detected properly so
       ADMIN_UTL_MONITOR stored procedure does not issue
       RUNSTATS alerts for out-of-date statistics.
    

Local fix

  • n/a
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All DB2 for z/OS V9 and V10 users who use    *
    *                 index-on-expression (IOE) and join tables    *
    *                 with multiple CCSIDs.                        *
    *                                                              *
    *              Also for all DB2 for z/OS V10 users who use DB2 *
    *              REAL-TIME STATISTICS for REORG suggestions.     *
    ****************************************************************
    * PROBLEM DESCRIPTION: There are two problem fixed by this     *
    *                      APAR.                                   *
    *                                                              *
    *                      The first problem may occur on both V9  *
    *                      and V10.  DB2 may produce incorrect     *
    *                      output when a UNICODE table joins to    *
    *                      an EBCDIC view which is a UNION ALL,    *
    *                      and at the same time, when              *
    *                      index-on-expression (IOE) is used       *
    *                      for that query.                         *
    *                                                              *
    *                      For example,                            *
    *                                                              *
    *                      CREATE VIEW MY_EBCDIC_VIEW (...) AS     *
    *                      (SELECT DISTINCT ...                    *
    *                         FROM ...                             *
    *                         WHERE ...                            *
    *                       UNION ALL                              *
    *                       SELECT DISTINCT ...                    *
    *                         FROM ...                             *
    *                         WHERE ...);                          *
    *                                                              *
    *                      SELECT ...                              *
    *                      FROM MY_UNICODE_TABLE, MY_EBCDIC_VIEW   *
    *                      WHERE ...;                              *
    *                                                              *
    *                      And for the query, DB2 chooses IOE      *
    *                      to access MY_UNICODE_TABLE.             *
    *                                                              *
    *                      The second problem is V10 only. DB2     *
    *                      may not issue a REORG suggestion as     *
    *                      it should. This problem is related to   *
    *                      DB2 V10 REAL-TIME STATISTICS.           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    There are two problem fixed by this APAR.
    
    The first problem may occur on both V9 and V10.
    DB2 may produce incorrect output when a UNICODE table joins to
    an EBCDIC view which is a UNION ALL, and at the same time, when
    index-on-expression (IOE) is used for that query.
    
    It occurs because DB2 missed the multiple CCSID handling
    when IOE is used but the index access did not consume all
    the predicates on index keys for index matching or screening.
    
    The second problem is V10 only.
    DB2 may not issue a REORG suggestion as it should because the
    access path's senstivity to table clustering is not detected
    correctly.
    
    Additional Keywords:
    SQLINCORR SQLINCORROUT INCORROUT DB2INCORR/K REALTIMESTATS
    SQLCCSID SQLINDEXONEXP SQLVIEW SQLUNIONALL
    

Problem conclusion

  • The two problems are fixed.
    

Temporary fix

  • *********
    * HIPER *
    *********
    

Comments

APAR Information

  • APAR number

    PM75619

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-10-22

  • Closed date

    2013-02-13

  • Last modified date

    2013-03-04

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

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

    UK91647 UK91648

Modules/Macros

  •    DSNXOGP
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UK91647

       UP13/03/01 P F302

  • R910 PSY UK91648

       UP13/03/01 P F302

Fix is available

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Document information


More support for:

DB2 for z/OS

Software version:

A10

Reference #:

PM75619

Modified date:

2013-03-04

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