MIME-Version: 1.0
References: 
 <CAKK5BkESSc69sp2TiTWHvvOHCUey0rDWXSrR9pinyRqyfamUYg@mail.gmail.com>
 <AM9PR09MB49001B8EE023E0ADB715549E977DA@AM9PR09MB4900.eurprd09.prod.outlook.com>
In-Reply-To: 
 <AM9PR09MB49001B8EE023E0ADB715549E977DA@AM9PR09MB4900.eurprd09.prod.outlook.com>
From: Andrew Jackson <andrewjackson947@gmail.com>
Date: Thu, 5 Mar 2026 15:15:26 -0600
Message-ID: 
 <CAKK5BkH5sf8w2SvQ8Jrs+PBRbswDehuam4TRyvB4kC5Apoa9ag@mail.gmail.com>
Subject: Re: Add Option To Check All Addresses For Matching
 target_session_attr
To: Evgeny Kuzin <evgeny.kuzin@outlook.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Content-Type: multipart/alternative; boundary="0000000000003ae46e064c4d70e3"
Archived-At: 
 <https://www.postgresql.org/message-id/CAKK5BkH5sf8w2SvQ8Jrs%2BPBRbswDehuam4TRyvB4kC5Apoa9ag%40mail.gmail.com>
Precedence: bulk

--0000000000003ae46e064c4d70e3
Content-Type: text/plain; charset="UTF-8"

While I prefer your solution, I suspect that it would not be possible/worth
it to change the behavior at this point. It seems likely there is some
niche setup out there that relies on the current logic in some capacity.

I can imagine something along the lines of: someone sets up a hostname that
points to 2 IP records that each use different network infra or something
like that. In the case where you are looking for a primary you would not
want to duplicatively check the same host in this scenario because you
already confirmed that it is not the one you are looking for. With your
patch you would be increasing connection latency, probably not by that much
granted but this is the scenario that encouraged me to implement this as a
new parameter.

All that being said I'm fine with either patch and would love to see one of
them get merged. I suspect there are a lot of extraneous haproxy's that
have been set up in the wild that would be unneeded if one of our our
patches were merged and the changes proliferate to downstream drivers.

One note on your patch though: you may want to incorporate the unit tests
that I built out for this patch in yours.

--0000000000003ae46e064c4d70e3
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"auto">While I prefer your solution, I suspect that it would not=
 be possible/worth it to change the behavior at this point. It seems likely=
 there is some niche setup out there that relies on the current logic in so=
me capacity.=C2=A0<div dir=3D"auto"><br></div><div dir=3D"auto">I can imagi=
ne something along the lines of: someone sets up a hostname that points to =
2 IP records that each use different network infra or something like that. =
In the case where you are looking for a primary you would not want to dupli=
catively check the same host in this scenario because you already confirmed=
 that it is not the one you are looking for. With your patch you would be i=
ncreasing connection latency, probably not by that much granted but this is=
 the scenario that encouraged me to implement this as a new parameter.</div=
><div dir=3D"auto"><br></div><div dir=3D"auto">All that being said I&#39;m =
fine with either patch and would love to see one of them get merged. I susp=
ect there are a lot of extraneous haproxy&#39;s that have been set up in th=
e wild that would be unneeded if one of our our patches were merged and the=
 changes proliferate to downstream drivers.</div><div dir=3D"auto"><br></di=
v><div dir=3D"auto">One note on your patch though: you may want to incorpor=
ate the unit tests that I built out for this patch in yours.</div>
</div>

--0000000000003ae46e064c4d70e3--