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IC87348: IN A DPF ENVIRONMENT THE COLLECTION OF SECTION ACTUALS MIGHT SHOW "NA" AT SOME OPERATORS IN THE EXPLAIN OUTPUT

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • The problem can occur when all the following conditions are
    satisfied:
    
    1. DPF environment with table distributed across > 1 database
    partitions
    2. the query includes a predicate applied to the table access
    that indicates only a single database partition needs to be
    accessed, such as when the hash distribution key is bound to a
    constant value by means of an equality predicate or a predicate
    using the dbpartitionnum() function to filter rows only from a
    single database partition
    3. the query qualifies 0 rows from the table
    
    For example, if table T is hash distributed across multiple data
    partitions on column X, then the following query satisfies
    conditions 1 and 2:
    
    SELECT *
    FROM T
    WHERE X = 1
    
    If the table doesn't contain any rows matching "X=1", then
    condition 3 is satisfied and the section actuals information in
    the db2exfmt output will show "NA":
    
       Rows Actual
         RETURN
         (   1)
          Cost
           I/O
           |
            0
            0
         DTQ
         (   2)
         12.0482
           NA
           |
            0
           NA      <=== A value of NA is unexpected
         TBSCAN
         (   3)
         9.6526
           NA
           |
            0
           NA
     TABLE: TEST
          T1
           Q1
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * DPF                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 9.7 Fix Pack 8                                *
    ****************************************************************
    

Problem conclusion

  • DB2 9.7 Fix Pack 8 - Section actuals in a DPF environment for a
    predicate returning rows for one node will show operator values.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC87348

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-10-18

  • Closed date

    2013-04-08

  • Last modified date

    2013-04-08

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

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

    IC91294

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP

  • R970 PSY

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC87348

Modified date: 08 April 2013