From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alexander Korotkov <aekorotkov@gmail.com>
cc: =?UTF-8?Q?Darafei_Kom=D1=8Fpa_Praliaskouski?= <me@komzpa.net>,
        Nikita Glukhov <n.gluhov@postgrespro.ru>,
        pgsql-hackers <pgsql-hackers@postgresql.org>,
        Heikki Linnakangas <hlinnaka@iki.fi>, Fedor Sigaev <teodor@sigaev.ru>
Subject: Re: compress method for spgist - 2
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Comments: In-reply-to Alexander Korotkov <aekorotkov@gmail.com>
	message dated "Thu, 21 Sep 2017 02:27:50 +0300"
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Date: Wed, 20 Sep 2017 20:14:45 -0400
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Alexander Korotkov <aekorotkov@gmail.com> writes:
> On Thu, Sep 21, 2017 at 2:06 AM, Darafei "Komяpa" Praliaskouski <
> me@komzpa.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


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