IC89576: A NESTED CURSOR USING HASH JOIN OF 2 FRAGMENTED TABLES CAN RETURN BAD RESULTS IF PDQ IS ON

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APAR status

  • Closed as program error.

Error description

  • If you have a cursor defined for a query over 2 fragmented
    tables and the cursor is nested in another cursor and the query
    plan is using dynamic hash join method and the PDQPRIORITY is
    set to HIGH, the query may return bad results.
    

Local fix

  • When nested loop join method is forced by an optimizer directive
    AVOID_HASH, or the PDQPRIORITY is set to OFF, the problem
    doesn't reproduce.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All 11.70 users.                                             *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * A query may return incorrect result under the following      *
    * conditions:                                                  *
    *  - system has >=2 cpuvps                                     *
    *  - PDQ is on                                                 *
    *  - hash join is used, and there is no outer join, remote     *
    * table references in the query                                *
    *  - query is in a cursor that is executed multiple times      *
    *  - the hash join does not overflow in some executions of the *
    * cursor, but overflows in other executions, when it           *
    * overflows, wrong result may occur                            *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Update to IDS-11.70.xC8                                      *
    ****************************************************************
    

Problem conclusion

  • Problem Fixed In IDS-11.70.xC8
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC89576

  • Reported component name

    INFORMIX SERVER

  • Reported component ID

    5725A3900

  • Reported release

    B70

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-01-16

  • Closed date

    2014-02-26

  • Last modified date

    2014-02-26

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

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

Fix information

  • Fixed component name

    INFORMIX SERVER

  • Fixed component ID

    5725A3900

Applicable component levels

  • RB70 PSN

       UP



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Document information


More support for:

Informix Servers

Software version:

B70

Reference #:

IC89576

Modified date:

2014-02-26

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