Received: from makus.postgresql.org (makus.postgresql.org [98.129.198.125]) by mail.postgresql.org (Postfix) with ESMTP id 2E18C18BA22E for ; Wed, 18 Apr 2012 17:15:01 -0300 (ADT) Received: from sss.pgh.pa.us ([66.207.139.130]) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1SKbHI-0004fz-Ac for pgsql-docs@postgresql.org; Wed, 18 Apr 2012 20:15:00 +0000 Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id q3IKEiMR009774; Wed, 18 Apr 2012 16:14:44 -0400 (EDT) To: "Kevin Grittner" cc: cousinflo@free.fr, pgsql-docs@postgresql.org Subject: Re: Date/Time Types : internals In-reply-to: <4F8ED21402000025000470FA@gw.wicourts.gov> References: <4F8F0F71.20500@free.fr> <4F8ED21402000025000470FA@gw.wicourts.gov> Comments: In-reply-to "Kevin Grittner" message dated "Wed, 18 Apr 2012 14:39:16 -0500" Date: Wed, 18 Apr 2012 16:14:44 -0400 Message-ID: <9773.1334780084@sss.pgh.pa.us> From: Tom Lane X-Pg-Spam-Score: -1.9 (-) X-Archive-Number: 201204/37 X-Sequence-Number: 7291 "Kevin Grittner" writes: > I guess the point is that for hundreds of years, the same day could > have a different date depending which country's calendar you were > looking at. I'm not entirely clear why there's a problem if you > pick the Gregorian calendar and apply it retroactively. Which is, in fact, exactly what our code does. I think that bit in the docs is trying to explain why we do that rather than try to get the code to reflect what people really used back then. A possibly comparable point is that for timezone info we use the Olsen database (tzdata), which *does* make an effort to reflect historical realities. In consequence, at least once every several months we get somebody complaining about what a strange GMT offset he's seeing for timestamps before 1900 or so. If there's anyone out there who actually likes that behavior, we've not heard about it. (Not that I am going to try to get Olsen et al to change their policy.) regards, tom lane