public inbox for pgsql-docs@postgresql.org
help / color / mirror / Atom feedFrom: Bruce Momjian <bruce@momjian.us>
To: Robert Treat <rob@xzilla.net>
Cc: Kirk Parker <khp@equatoria.us>
Cc: Richard Neill <rjn@richardneill.org>
Cc: github@richardneill.org
Cc: pgsql-docs@lists.postgresql.org
Subject: Re: Please clarify that Timestamp with Timezone doesn't preserve the timezone.
Date: Thu, 14 May 2026 08:05:23 -0400
Message-ID: <agW6gzVtz73ZUjNn@momjian.us> (raw)
In-Reply-To: <CABV9wwPSTVtyBpe8J2kJ1JA29ZKTVtB3+Wjo2gFLJYWZCbqo-Q@mail.gmail.com>
References: <177685804902.403059.7237129094698721575@wrigleys.postgresql.org>
<agPDkRGXmdyD1EcR@momjian.us>
<ddf41f033a8add84e1f28a095defafae@richardneill.org>
<agR45nws-Y1StCCH@momjian.us>
<CANwZ8rmZdajKmt1KmTRhO7ex-RUeQNwu7yQw19mWaR08B+BdHA@mail.gmail.com>
<agS4qwKSeb-8CrJc@momjian.us>
<CABV9wwPSTVtyBpe8J2kJ1JA29ZKTVtB3+Wjo2gFLJYWZCbqo-Q@mail.gmail.com>
On Thu, May 14, 2026 at 07:57:21AM -0400, Robert Treat wrote:
> > I see your point. I went with adding the wording "no time zone
> > adjustment" and "with time zone adjustment" in the table. Patch
> > attached. You can see the output at:
>
> The quibble I have with the term "time zone adjustment" is that it
> implies there will be some adjustment, but while you can change your
> timezone preferences to display a timestamptz value in whatever time
> zone you want, the value itself is never adjusted; it is stored as a
> universal moment in time that doesn't change, regardless of the window
> dressing around it. For this reason I have taken to describing that
> difference between the two as that timestamptz stores the date and
> time with timezone awareness, and timestamp is date and time with no
> timezone awareness. Perhaps that might work better here as well?
I used "adjustment" because the value is adjusted on input, and adjusted
on output. I would say the value is not "aware" of the time zone
because once it is internally stored as UTC it is no longer aware of the
original time zone.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Do not let urgent matters crowd out time for investment in the future.
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-docs@postgresql.org
Cc: bruce@momjian.us, rob@xzilla.net, khp@equatoria.us, rjn@richardneill.org, github@richardneill.org, pgsql-docs@lists.postgresql.org
Subject: Re: Please clarify that Timestamp with Timezone doesn't preserve the timezone.
In-Reply-To: <agW6gzVtz73ZUjNn@momjian.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox