IBM Support

LI77081: NEGATIVE CARDINALITY AND NEGATIVE TIMERON COSTS IN EXPLAIN PLAN

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as fixed if next.

Error description

  • Negative cardinality and negative timeron costs may appear in an
    explain plan if
    
    1. It is a DPF environment with a large number of nodes
    
    and
    
    2. The explained query has a large value in the FETCH FIRST N
    ROWS clause or LIMIT clause
    
    
    For example,
    
       -4.88064e+06
          INSERT
          (   4)
          -997290
           3900
    
    
    This issue does not affect the actual query execution, as no
    errors will be returned, but it does reduce the users' ability
    to make informed query tuning decisions; without valid
    cardinality and timeron cost estimates, the work performed at
    various access plan operations cannot be meaningfully assessed.
    

Local fix

  • Reduce the value specified in the FETCH FIRST N ROWS or LIMIT
    clauses.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * ALL                                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * See SYSROUTE APARs to see where this APAR is addressed       *
    ****************************************************************
    

Problem conclusion

Temporary fix

Comments

APAR Information

  • APAR number

    LI77081

  • Reported component name

    DB2 UDE ESE LIN

  • Reported component ID

    5765F4104

  • Reported release

    950

  • Status

    CLOSED FIN

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2012-10-31

  • Closed date

    2017-05-09

  • Last modified date

    2017-05-09

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

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

    IC91691

Fix information

Applicable component levels

  • R950 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 950

Reference #: LI77081

Modified date: 09 May 2017