Feedback-ID: i0fe9450f:Fastmail
Date: Tue, 7 Jul 2026 15:14:29 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Jelte Fennema-Nio <postgres@jeltef.nl>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	Alvaro Herrera <alvherre@alvh.no-ip.org>,
	Jacob Champion <jacob.champion@enterprisedb.com>
Subject: Re: Don't use the deprecated and insecure PQcancel in our frontend
 tools anymore
Message-ID: <akyZRUQovOCutJ9_@paquier.xyz>
References: <DG9TD0OX13DP.2JAB9LIS2HTLO@jeltef.nl>
 <88dfe280-ba29-4943-95b8-63abc9f3f771@iki.fi>
 <DGVC3GZ0U1NS.3P1XEU5E065XQ@jeltef.nl>
 <9d7ba3ac-d660-483e-8f68-9096a2464e90@iki.fi>
 <DH3G8Z262WNH.DMDDI1DM95OG@jeltef.nl>
 <d102a894-409b-43cd-a164-eaf416077ff4@iki.fi>
 <DH4ZKYOWSPRN.2L0Z3WDBG9FC8@jeltef.nl>
 <b0e6a640-5aed-469f-867a-cc820b046798@iki.fi>
 <DJPAH0WPJV3K.1PYZ8P0QXZVMX@jeltef.nl>
 <aea19cfb-0518-4485-b3d8-c7647d450186@iki.fi>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
	protocol="application/pgp-signature"; boundary="IZJpVyRdjax4bd0H"
Content-Disposition: inline
In-Reply-To: <aea19cfb-0518-4485-b3d8-c7647d450186@iki.fi>
Archived-At: 
 <https://www.postgresql.org/message-id/akyZRUQovOCutJ9_%40paquier.xyz>
Precedence: bulk


--IZJpVyRdjax4bd0H
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Sat, Jul 04, 2026 at 10:11:54PM +0300, Heikki Linnakangas wrote:
> On 04/07/2026 01:28, Jelte Fennema-Nio wrote:
>> 5d43c3c54 mentions the --single-step flag as something that required
>> further analysis. I tried --single-step with and without this commit,
>> and Ctrl+C behaves the same in both. I also cannot think of a reason why
>> it would behave any differently.
>=20
> Hmm, me neither. Michael, it was a long time ago, but would you happen to
> remember what your concern on that was?

I unfortunately do not have anymore my notes from 2019 lying around,
but looking at the other thread and the code, it seems to me that the
problem I saw back then is that cancel request was not working at all
under --single-step because we would not set the flag when PQcancel()
failed.  Back around 5d43c3c54 the CancelRequest flag was only set
after we've successfully sent a request.  92f33bb7afd3 has changed
that globally, by setting the flag even if a cancel request could not
be sent.  So back then I am pretty sure that my line of thoughts
turned around the case where PQcancel() failed.
--
Michael

--IZJpVyRdjax4bd0H
Content-Type: application/pgp-signature; name=signature.asc

-----BEGIN PGP SIGNATURE-----
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=roeE
-----END PGP SIGNATURE-----

--IZJpVyRdjax4bd0H--