Re: pgsql: Protect GIST logic that assumes penalty values can't be negative

Greg Stark <gsstark(at)mit(dot)edu> writes:
> On Tue, May 31, 2011 at 2:54 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Prevent problems by clamping negative penalty values to
>> zero. (Just to be really sure, I also made it force NaNs to zero.)

> Do gistchoose et al expect the triangle function to obey the triangle
> inequality?

Don't think so.

> If so isn't it possible treating NaNs as zero would fail
> that? I'm not sure there's any safe assumption for NaN

Well, leaving it as NaN is almost certain to not work desirably.

regards, tom lane