Overview of BMC AMI Stats

BMC AMI Stats collects statistics about the characteristics of Db2 objects, and writes them to the IBM Db2 catalog, to the BMC statistical repository tables, or optionally to your history tables. You can specify which statistics to write and which reports to generate.

Specifically, BMC AMI Stats collects:

Related topic

 Getting-started-with-BMC-AMI-Stats

  • Statistics for table spaces, tables, and indexes
  • Column statistics for columns
  • Distributed statistics for columns

Important

To avoid the overhead that is required to sort columns, BMC uses an estimation algorithm to generate column cardinality and frequency statistics.

NGTSTATS is delivered with +FREQ(NONE) as the default in the configuration file. This default prevents NGTSTATS from collecting frequency distribution statistics on the indexes. IBM RUNSTATS defaults to collect frequency distribution statistics on the first key of each index, which defaults to FREQVAL NUMCOLS(1) COUNT(10) MOST.

Following are methods for making NGTSTATS collect the frequency distribution statistics in the same way as IBM RUNSTATS:

  • Change +FREQ(NONE) to +FREQ(MOST) in the configuration file. Because NUMCOLS defaults to 1 and COUNT defaults to 10, this change causes NGTSTATS to capture the same frequency distribution data as IBM RUNSTATS. Changing the configuration file causes these parameters to apply to NGTREORG and NGTLOAD.
  • Provide the following parameters in the STTPARMS DD:
    +FREQ(MOST)
    +NUMCOLS(1)
    +COUNT(10)
    Using these parameters, you can collect frequency distribution statistics without specifying KEYCARD FREQVAL NUMCOLS 1 COUNT 10 MOST.
  • Specify “KEYCARD FREQVAL NUMCOLS 1 COUNT 10 MOST”. 

You can use BMC AMI Stats with BMC AMI Utility Manager.


 

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