On 14 Dec 2013 15:40, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> > The attached patch is not quite finished yet, I've not yet fully covered
> > SUM and AVG for all types.
>
> I think you *can't* cover them for the float types; roundoff error
> would mean you don't get the same answers as before.
I was going to say the same thing. But then I started to wonder.... What's
so special about the answers we used to give? They are also subject to
round off and the results are already quite questionable in those cases.