AlexK987 <alex.cue.987@gmail.com> writes:
> I believe that tables' clustering factors are stored in pg_stats.correlation.
Dunno what you mean by "clustering factor", but pg_stats.correlation
stores the correlation coefficient between the sequence of the column's
data values and the sequence of their physical order. Correlation
coefficient is defined in the usual way:
http://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient
so it ranges between +1 in your example (perfect ordering) and -1
(perfect descending order).
regards, tom lane
