Hi all!

A user has asked for more information about column statistics. He would like to get

- Column's Most Common Value (MCV)
- The frequency of the most common value, call this Most Common Frequency (MCF)
- Histogram information

This would be provided through a monitoring table, most likely.

DB2 has this, and it seems that Oracle can maintain histogram statistics, too. Here are some articles on this, for DB2 and Oracle,
http://www.craigmullins.com/dbu_0308.htm.
http://www.dba-oracle.com/art_builder_histo.htm

I *think* that this information is only useful to the optimizer if we implement HASH join, which we don't have now, I may be wrong on this.

For now, it is fine that I capture the requirement of providing the MCV, MCF, and histogram information through monitoring tables when/if it becomes available. I looked for a ticket adding HASH JOIN's but didn't see it... Don't we have this somewhere?

-bill

Bill Oliver
Product Specialist, Base SAS
SAS Institute - The Power To Know
bill.oliver@...
919-531-0675