From: Tom Lane <tgl@sss.pgh.pa.us>
To: Simon Riggs <simon.riggs@enterprisedb.com>
cc: "Watzinger, Alexander" <Alexander.Watzinger@oeaw.ac.at>,
        "pgsql-general@lists.postgresql.org"
 <pgsql-general@lists.postgresql.org>
Subject: Re: Support for dates before 4713 BC
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Comments: In-reply-to Simon Riggs <simon.riggs@enterprisedb.com>
	message dated "Mon, 12 Sep 2022 16:41:19 +0100"
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Date: Mon, 12 Sep 2022 11:53:25 -0400
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Simon Riggs <simon.riggs@enterprisedb.com> writes:
> On Mon, 12 Sept 2022 at 16:00, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> No, it applies because we aren't sure that the math would operate
>> correctly with negative Julian day numbers --- for instance, division
>> roundoffs might happen in the wrong direction.  If somebody wanted to go
>> through and check/fix all that, we could probably relax the restriction.

> OK, challenge seems clear.

FWIW, I think this decision dates to a time when we still worried about
C89's lack of specificity about which direction integer division will
round negative results in.  Now that we're targeting only C99-compliant
platforms, that part should be easier.

			regards, tom lane