From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Thomas Munro <thomas.munro@gmail.com>
Cc: Petr Fedorov <petr.fedorov@phystech.edu>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Since '2001-09-09 01:46:40'::timestamp microseconds are lost when extracting epoch
Date: Mon, 25 May 2020 09:43:32 -0400
Message-ID: <27490.1590414212@sss.pgh.pa.us> (raw)
In-Reply-To: <ee683994-8f7c-aded-be43-543e66e68b94@2ndquadrant.com>
References: <42b73d2d-da12-ba9f-570a-420e0cce19d9@phystech.edu>
<CA+hUKGKgHUbFNKRhvodn4mVU-oqje+HA7jTg_XrWRo4UGhFoqg@mail.gmail.com>
<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>
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.
regards, tom lane
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To: pgsql-bugs@postgresql.org
Cc: tgl@sss.pgh.pa.us, peter.eisentraut@2ndquadrant.com, thomas.munro@gmail.com, petr.fedorov@phystech.edu, pgsql-hackers@postgresql.org
Subject: Re: Since '2001-09-09 01:46:40'::timestamp microseconds are lost when extracting epoch
In-Reply-To: <27490.1590414212@sss.pgh.pa.us>
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