Re: compress method for spgist - 2

Alexander Korotkov <aekorotkov(at)gmail(dot)com> writes:
> On Thu, Sep 21, 2017 at 2:06 AM, Darafei "Komяpa" Praliaskouski <
> me(at)komzpa(dot)net> wrote:
>> What is rationale behind this circle?

> I would prefer to rather forbid any geometries with infs and nans.
> However, then upgrade process will suffer. User with such geometries would
> get errors during dump/restore, pg_upgraded instances would still contain
> invalid values...

Yeah, that ship has sailed unfortunately.

>> It seems to me that any circle with radius of any Infinity should become a
>> [-Infinity .. Infinity, -Infinity .. Infinity] box.Then you won't have
>> NaNs, and index structure shouldn't be broken.

> We probably should produce [-Infinity .. Infinity, -Infinity .. Infinity]
> box for any geometry containing inf or nan.

Hm, we can do better in at least some cases, eg for a box ((0,1),(1,inf))
there's no reason to give up our knowledge of finite bounds for the
other three boundaries. But certainly for a NaN circle radius
what you suggest seems the most sensible thing to do.

regards, tom lane