Re: B-Tree support function number 3 (strxfrm() optimization)

On Fri, Sep 12, 2014 at 12:02 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> I think I've said a few times now that I really want to get this
> additional data before forming an opinion.  As a certain Mr. Doyle
> writes, "It is a capital mistake to theorize before one has data.
> Insensibly one begins to twist facts to suit theories, instead of
> theories to suit facts."  I can't say it any better than that.

Well, in the abbreviated key case we might know that with probability
0.99999 that the "memcmp() == 0" thing will work out. In the
non-abbreviated tie-breaker case, we'll definitely know nothing. That
seems like a pretty fundamental distinction, so I don't think it's
premature to ask you to consider those two questions individually.
Still, maybe it's easier to justify both cases in the same way, if we
can.

-- 
Peter Geoghegan