Date: Mon, 25 May 2020 21:29:21 +0200
From: David Fetter <david@fetter.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>,
	Thomas Munro <thomas.munro@gmail.com>,
	Petr Fedorov <petr.fedorov@phystech.edu>,
	pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Since '2001-09-09 01:46:40'::timestamp microseconds are lost
 when extracting epoch
Message-ID: <20200525192921.GL13741@fetter.org>
References: <42b73d2d-da12-ba9f-570a-420e0cce19d9@phystech.edu>
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 <18389.1575241151@sss.pgh.pa.us>
 <1c2262e2-6812-7baa-cbdd-63039db12952@phystech.edu>
 <CA+hUKGK+K8NyS57tU841m1tSF6ha3W0udN2dw_Hbc=D_0OPbmA@mail.gmail.com>
 <ee683994-8f7c-aded-be43-543e66e68b94@2ndquadrant.com>
 <27490.1590414212@sss.pgh.pa.us>
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On Mon, May 25, 2020 at 09:43:32AM -0400, Tom Lane wrote:
> Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes:
> > One problem (other than perhaps performance, tbd.) is that this would no 
> > longer allow processing infinite timestamps, since numeric does not 
> > support infinity.  It could be argued that running extract() on infinite 
> > timestamps isn't very useful, but it's something to consider explicitly.
> 
> I wonder if it's time to fix that, ie introduce +-Infinity into numeric.c.
> This isn't the first time we've seen issues with numeric not being a
> superset of float, and it won't be the last.
> 
> At first glance there's no free bits in the on-disk format for numeric,
> but we could do something by defining the low-order bits of the header
> word for a NaN to distinguish between real NaN and +/- infinity.
> It looks like those bits should reliably be zero right now.

+1 for adding +/- infinity to NUMERIC.

Best,
David.
-- 
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778

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