Histograms

Does anyone have any firm ideas about
how Oracle calculates the column DENSITY when creating a histogram ?

There seem to be at least three strategies, one of which may be out of date - one which seems to apply only for small numbers of distinct values, and the generic case which has me completely baffled.

Any insights would be appreciated.

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

Coming soon a new one-day tutorial:
Cost Based Optimisation
(see http://www.jlcomp.demon.co.uk/tutorial.html )

Next Seminar dates:
(see http://www.jlcomp.demon.co.uk/seminar.html )

____England______January 21/23

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