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 4.94.2)
	(envelope-from <pgsql-hackers-owner+archive@lists.postgresql.org>)
	id 1t16yb-00Emi5-BC
	for pgsql-hackers@arkaria.postgresql.org; Wed, 16 Oct 2024 16:34:21 +0000
Received: from localhost ([127.0.0.1] helo=malur.postgresql.org)
	by malur.postgresql.org with esmtp (Exim 4.94.2)
	(envelope-from <pgsql-hackers-owner+archive@lists.postgresql.org>)
	id 1t16yZ-005sdR-Kl
	for pgsql-hackers@arkaria.postgresql.org; Wed, 16 Oct 2024 16:34:20 +0000
Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29])
	by malur.postgresql.org with esmtps  (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.94.2)
	(envelope-from <daniel@manitou-mail.org>)
	id 1t16yZ-005sdI-BS
	for pgsql-hackers@lists.postgresql.org; Wed, 16 Oct 2024 16:34:19 +0000
Received: from dverite2024.planet-service.net ([185.16.44.252] helo=mail.verite.pro)
	by magus.postgresql.org with esmtps  (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
	(Exim 4.94.2)
	(envelope-from <daniel@manitou-mail.org>)
	id 1t16yW-001NxT-08
	for pgsql-hackers@lists.postgresql.org; Wed, 16 Oct 2024 16:34:19 +0000
Received: by mail.verite.pro (Postfix, from userid 1000)
	id EDB072C84E1; Wed, 16 Oct 2024 18:34:13 +0200 (CEST)
Content-Type: text/plain; charset="iso-8859-15"
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
From: "Daniel Verite" <daniel@manitou-mail.org>
Subject: Re: New "raw" COPY format
To: "Joel Jacobson" <joel@compiler.org>
Cc: Jacob Champion <jacob.champion@enterprisedb.com>,
 Tatsuo Ishii <ishii@postgresql.org>,
 pgsql-hackers@lists.postgresql.org
In-Reply-To: <d3969244-c4b0-40e1-b178-781345c6008b@app.fastmail.com>
Date: Wed, 16 Oct 2024 18:34:13 +0200
Message-Id: <d3313604-fbdd-483f-9c29-aceaf491f949@manitou-mail.org>
X-Mailer: Manitou v1.7.3
List-Id: <pgsql-hackers.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-hackers@lists.postgresql.org>
List-Owner: <mailto:pgsql-hackers-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-hackers>
Archived-At: <https://www.postgresql.org/message-id/d3313604-fbdd-483f-9c29-aceaf491f949%40manitou-mail.org>
Precedence: bulk

	Joel Jacobson wrote:

> However, I thinking rejecting such column data seems like the
> better alternative, to ensure data exported with COPY TO
> can always be imported back using COPY FROM,
> for the same format.=20

On the other hand, that might prevent cases where we
want to export, for instance, a valid json array:

  copy (select json_agg(col) from table ) to 'file' RAW

This is a variant of the discussion in [1] where the OP does:

 copy (select json_agg(row_to_json(t)) from <query> t) TO 'file'=20

and he complains that both text and csv "break the JSON".
That discussion morphed into a proposed patch adding JSON
format to COPY,  but RAW would work directly as the OP
expected.

That is, unless <query> happens to include JSON fields with LF/CRLF
in them, and the RAW format says this is an error condition.
In that case it's quite annoying to make it an error, rather than
simply let it pass.


[1]
https://postgr.es/m/CALvfUkBxTYy5uWPFVwpk_7ii2zgT07t3d-yR_cy4sfrrLU=3Dkcg@m=
ail.gmail.com


Best regards,
--=20
Daniel V=E9rit=E9
https://postgresql.verite.pro/
Twitter: @DanielVerite