RE: UncompBkts: what is it? (reference to 10053 trace)
- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxxxxx>
- To: <sac@xxxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 27 Jul 2006 17:37:26 -0400
Charles,
You may consider Steve Adams' consider_histograms.sql script, available
here:
http://ixora.com.au/scripts/query_opt.htm
-Mark
--
Mark J. Bobak
Senior Oracle Architect
ProQuest Information & Learning
Ours is the age that is proud of machines that can think and suspicious
of men who try to. --H. Mumford Jones, 1892-1980
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Schultz, Charles
Sent: Thursday, July 27, 2006 4:15 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: UncompBkts: what is it? (reference to 10053 trace)
Google did not deign to tell me, so I am looking elsewhere.
In somewhat related terms, is there a set mathematical formula for "data
skew"? Folks talk about a "little skew" or "very skewed" data.
Practically any column is going to have at least some skew, but I have
to assume that there is a threshold whereby a given histogram (ie,
insufficient number of buckets) is going to hurt your performance.
charles schultz
oracle dba
aits - adsd
university of illinois
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