Date: Tue, 4 Sep 2018 22:35:35 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL-documentation <pgsql-docs@postgresql.org>
Subject: Re: AT TIME ZONE correction
Message-ID: <20180905023535.GC13695@momjian.us>
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On Mon, Sep  3, 2018 at 09:20:34AM -0400, Bruce Momjian wrote:
> On Sun, Sep  2, 2018 at 10:11:59PM -0400, Bruce Momjian wrote:
> > On Sun, Sep  2, 2018 at 02:21:58PM -0400, Tom Lane wrote:
> > > I still find this to be more confusing than helpful.  In particular,
> > > I do not think that it's possible to explain this behavior clearly
> > > without mentioning that timestamp with time zone values are always
> > > stored in UTC and what AT TIME ZONE really does is convert between UTC
> > > and the specified zone (in a direction dependent on which type is
> > > supplied as argument).
> > 
> > Agreed.  The more I dig into this the more I learn.  I have developed
> > the attached patch which I hope this time is an improvement.
> 
> I polished the text some more and changed the three-letter time zone
> abbreviation (e.g., MST) to use the more general text, e.g.
> "America/Denver".  We should not be encouraging people to specify the
> daylight savings time status based on the date in the date/time string.

Patch applied through 9.3.  I ended up adding a third example:

	https://git.postgresql.org/pg/commitdiff/dd6073f22a6b5dd6181d8324465dd3c0bf1851e8

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +