Re: Correlation in cost_index()

Manfred Koizar <mkoi-pg@aon.at> writes:
> Never mind!  I just stumbled over those lines in selfuncs.c where
> indexCorrelation is calculated by dividing the correlation of the
> first index column by the number of index columns.

Yeah, I concluded later that that was bogus.  I've been thinking of
just using the correlation of the first index column and ignoring
the rest; that would not be great, but it's probably better than what's
there.  Have you got a better formula?
        regards, tom lane