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Object documentation Log Table for Update Statistics with SAPDBA  Locate the document in its SAP Library structure

Definition

The log table DBSTATTINF contains details of update statistics.

Use

Every time you run update statistics with SAPDBA for Informix, DBSTATTINF is updated with details of the tables that have been checked and of the tables that have had new statistics generated.

Structure

One row is updated in DBSTATTINF for each table processed by update statistics. The most important fields for this are as follows:

Field

Comment

tabname

Table name

lupdstat

Date and time of the last update statistics with SAPDBA.

Format: yyyymmddhhmm

cupdstat

Date of the last "check statistics"

threshold

Threshold for the update statistics — in other words, the percentage deviation between the statistics and the current (that is, correct) number of rows in the table

value

Update statistics level, in format char(3) as follows:

  • 1st char = level for heading index columns
  • 2nd char = level for non-heading index columns
  • 3rd char = level for non-index columns

For example, HMN means:

  • High for heading index columns
  • Medium for non-heading index columns
  • None for non-index columns

duration

Duration of update statistics in seconds

Integration

To find out which tables have had their statistics updated by a run of update statistics, you can enter an SQL command like the following using the Informix tool DBACCESS :

Select *
from dbstattinf
where lupdstat like "<date of the last update statistics run>%"
and tabname = "<table name>"
;

For example, for a run of update statistics on the 23rd January 1999 that might possibly have affected table a014 :

Select *
from dbstattinf
where lupdstat like "19990123%"
and tabname = "a014"
;

If a row is returned from this query, this means that table a014 has had its statistics updated on this date. Examine the row to find out what has happened.

If you used cupdstat in the above query, you can find out if a table has had its statistics checked on this date. For more information, see the section on the check parameter in Update Statistics from the Command Line. During an update statistics run, tables where the threshold is not reached do not have the field lupdstat updated. Instead, the field cupdstat is updated.

 

See also:

Informix documentation