IC89650: PERFORMANCE ISSUE WITH A CORRELATED SUBQUERY THAT USES A COMPLEX VIEW USED IN A NOT EXISTS CLAUSE

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APAR status

  • Closed as program error.

Error description

  • The following query is extremely slow in IDS.
    
    select
            x0.client ,x0.tdate ,x0.nbr ,x0.name
            ,x0.c ,x0.s ,x0.z ,x0.country
    ,x0.p_nbr
            ,x0.b_by_a ,x0.b_date ,x0.qty
    ,x0.stat
            ,x0.cdate ,x0.sbus ,x0.gamt
    ,x0.namt
            ,x0.aamt ,x0.tamt
    from
            "informix".test x0
    where
            NOT EXISTS (select 1 from "informix".r_test
    x1 where
                    ((x0.client = x1.cfile ) AND
    (x0.tdate =
                                    x1.trand ) ) ) ;
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All 11.70 users.                                             *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * A query may experience slow performance under the following  *
    * conditions:                                                  *
    *   - there is a correlated subquery in the where clause       *
    *   - the correlated subquery cannot be flattened into the     *
    * main query, e.g., a NOT EXISTS subquery                      *
    *   - the correlated subquery references a view or derived     *
    * table                                                        *
    *   - the view referenced has more than one table in its       *
    * definition, tables referenced lack indexes on join columns,  *
    * and at least one of the referenced tables is large (hundreds *
    * of thousands to millions of rows).                           *
    *   - inside the view definition there is a nested view        *
    * reference                                                    *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Update to IDS-11.70.xC8                                      *
    ****************************************************************
    

Problem conclusion

  • Problem Fixed In IDS-11.70.xC8
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC89650

  • Reported component name

    INFORMIX SERVER

  • Reported component ID

    5725A3900

  • Reported release

    B70

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-01-18

  • 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 #:

IC89650

Modified date:

2014-02-26

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