Re: Minmax indexes

On Mon, Nov 11, 2013 at 12:53 AM, Erik Rijkers <er(at)xs4all(dot)nl> wrote:

> On Fri, November 8, 2013 21:11, Alvaro Herrera wrote:
> >
> > Here's a version 7 of the patch, which fixes these bugs and adds
> > opclasses for a bunch more types (timestamp, timestamptz, date, time,
> > timetz), courtesy of Martín Marqués. It's also been rebased to apply
> > cleanly on top of today's master branch.
> >
> > I have also added a selectivity function, but I'm not positive that it's
> > very useful yet.
> >
> > [minmax-7.patch]
>
> The earlier errors are indeed fixed; now, I've been trying with the
> attached test case but I'm unable to find a query that
> improves with minmax index use. (it gets used sometimes but speedup is
> negligable).
>

Your data set seems to be completely random. I believe that minmax indices
would only be expected to be useful when the data is clustered. Perhaps
you could try it on a table where it is populated something like
i+random()/10*max_i.

Cheers,

Jeff