Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1wNc0m-000wHE-15 for pgsql-docs@arkaria.postgresql.org; Thu, 14 May 2026 19:46:24 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.96) (envelope-from ) id 1wNc0i-00EmC9-1r for pgsql-docs@arkaria.postgresql.org; Thu, 14 May 2026 19:46:20 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1wNc0i-00EmBz-0h for pgsql-docs@lists.postgresql.org; Thu, 14 May 2026 19:46:20 +0000 Received: from momjian.us ([72.94.173.45]) by makus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wNc0f-00000000aeC-3jyb for pgsql-docs@lists.postgresql.org; Thu, 14 May 2026 19:46:19 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=momjian.us; s=2026010100; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description; bh=7G6T1SrxxrUq75MdF2/y4bHSql5fm039iECl1+jd16U=; b=lwH1T gVu5xF9DocD9stLHmpDCmeuPY6cas+NzvGFw6buZ+UkQYprwpZwtnbCoGBzHWDzF2cGlSx8bmlhpb qTVe9WA9GG7lcgcjzWhAOlKgB8Mpno4jjLV2wBgQlViZ9pHZksBg5WZaJrg43FWzripUtRReEFhyc 0f5spNC4Sz9AxauSYaofx/Ew2Cow9qzd3mZ8jF24h4sPna5INGBjGuSWKix8C5m/TRF+MOHZPcVnt d6Pw5VqoNo8E8LVCpYp0gcJ/qs1ooU/e+bdfT0AmCES760SWc8bZ30etjGhgG07E9vARyyYqLgUyr VCuzuelzZzf4bEJfEEkcLgI1J9GgQ==; Received: from bruce by momjian.us with local (Exim 4.98.2) (envelope-from ) id 1wNc0c-0000000H5C9-0oTh; Thu, 14 May 2026 15:46:14 -0400 Date: Thu, 14 May 2026 15:46:14 -0400 From: Bruce Momjian To: Tom Lane Cc: Dave Cramer , Robert Treat , Kirk Parker , Richard Neill , github@richardneill.org, pgsql-docs@lists.postgresql.org Subject: Re: Please clarify that Timestamp with Timezone doesn't preserve the timezone. Message-ID: References: <1018713.1778781735@sss.pgh.pa.us> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="hkFz0MsXOi0IO2L3" Content-Disposition: inline In-Reply-To: <1018713.1778781735@sss.pgh.pa.us> List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk --hkFz0MsXOi0IO2L3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, May 14, 2026 at 02:02:15PM -0400, Tom Lane wrote: > Bruce Momjian writes: > > Okay, here is the patch with "conversion". > > timetz does store a UTC offset, so it needs to be discussed separately. > I don't think applying the same verbiage to time and timestamp will > produce anything except more confusion. I see what you mean --- updated patch attached. If we want to be more explicit we could change "including time zone conversion" to "including time zone conversion to/from UTC". -- Bruce Momjian https://momjian.us EDB https://enterprisedb.com Do not let urgent matters crowd out time for investment in the future. --hkFz0MsXOi0IO2L3 Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="time_zone.diff" diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index d8d91678e86..339fec8ac08 100644 --- a/doc/src/sgml/datatype.sgml +++ b/doc/src/sgml/datatype.sgml @@ -264,13 +264,13 @@ timestamp [ (p) ] [ without time zone ] - date and time (no time zone) + date and time (no time zone conversion) timestamp [ (p) ] with time zone timestamptz - date and time, including time zone + date and time, including time zone conversion @@ -1768,7 +1768,7 @@ SELECT 'abc \153\154\155 \052\251\124'::bytea; timestamp [ (p) ] [ without time zone ] 8 bytes - both date and time (no time zone) + both date and time (no time zone conversion) 4713 BC 294276 AD 1 microsecond @@ -1776,7 +1776,7 @@ SELECT 'abc \153\154\155 \052\251\124'::bytea; timestamp [ (p) ] with time zone 8 bytes - both date and time, with time zone + both date and time, with time zone conversion 4713 BC 294276 AD 1 microsecond @@ -2263,8 +2263,9 @@ TIMESTAMP WITH TIME ZONE '2004-10-19 10:23:54+02' then it is assumed to be in the time zone indicated by the system's parameter, and is converted to UTC using the offset for the timezone zone. - In either case, the value is stored internally as UTC, and the - originally stated or assumed time zone is not retained. + In either case, the value is stored internally as UTC. The + originally stated or assumed time zone is not retained and + cannot be retrieved later. --hkFz0MsXOi0IO2L3--