From: | Greg Stark <gsstark(at)mit(dot)edu> |
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To: | Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> |
Cc: | Greg Stark <gsstark(at)mit(dot)edu>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Cross column statistics |
Date: | 2005-02-08 17:51:25 |
Message-ID: | 87u0oney8y.fsf@stark.xeocode.com |
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Lists: | pgsql-hackers |
Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> writes:
> > B) gather a full matrix of the level of "correlation" between each column and
> > each other column. If this were a single floating point number per pair
> > then it might be feasible. It would still obviously be n^2 in the number of
> > columns though, so there would have to be some way to limit on how many
> > columns would be analyzed this way.
>
> Use foreign keys to just record those cross-correlations.
My email was about cross-column intra-table "correlations". inter-table
"correlations" are a whole other ball of wax.
--
greg
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