Re: Thoughts on statistics for continuously advancing columns

Josh Berkus <josh@agliodbs.com> writes:
> My thoughts on dealing with this intelligently without a major change to
> statstics gathering went along these lines:

> 1. add columns to pg_statistic to hold estimates of upper and lower
> bounds growth between analyzes.

This seems like a fundamentally broken approach, first because "time
between analyzes" is not even approximately a constant, and second
because it assumes that we have a distance metric for all datatypes.
(Note that convert_to_scalar does not assume that it can measure
arbitrary distances, but only fractions *within* a histogram bucket;
and even that is pretty shaky.)

I don't have a better idea at the moment :-(
        regards, tom lane