straight join on columns with frequency histograms
- From: "Alberto Dell'Era" <alberto.dellera@xxxxxxxxx>
- To: oracle-l <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 6 Oct 2006 18:28:57 +0200
Dear List,
I'm currently investigating, for a complex issue I have
but also "just for fun", the CBO formula used for the estimation
of the cardinality of
select ...
from t1, t2
where t1.x = t2.x;
where both t1.x and t2.x have *frequency* histograms associated.
Has anyone already investigated something similar, and likes
to share the results with me ?
I have already discovered "most" of the formula, that
looks simple and intuitive, minus some "border" cases
that I'm currently investigating - but I would like to
avoid reinventing the wheel if someone has already
discovered the full formula.
Thanks in advance
Alberto
--
Alberto Dell'Era
"Per aspera ad astra"
--
//www.freelists.org/webpage/oracle-l
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