public inbox for [email protected]  
help / color / mirror / Atom feed
From: Jacob Champion <[email protected]>
To: [email protected]
Subject: pgsql: pg_upgrade: Use max_protocol_version=3.0 for older servers
Date: Tue, 24 Feb 2026 22:33:17 +0000
Message-ID: <[email protected]> (raw)

pg_upgrade: Use max_protocol_version=3.0 for older servers

The grease patch in 4966bd3ed found its first problem: prior to the
February 2018 patch releases, no server knew how to negotiate protocol
versions, so pg_upgrade needs to take that into account when speaking to
those older servers.

This will be true even after the grease feature is reverted; we don't
need anyone to trip over this again in the future. Backpatch so that all
supported versions of pg_upgrade can gracefully handle an update to the
default protocol version. (This is needed for any distributions that
link older binaries against newer libpqs, such as Debian.) Branches
prior to 18 need an additional version check, for the existence of
max_protocol_version.

Per buildfarm member crake.

Reviewed-by: Tom Lane <[email protected]>
Discussion: https://postgr.es/m/CAOYmi%2B%3D4QhCjssfNEoZVK8LPtWxnfkwT5p-PAeoxtG9gpNjqOQ%40mail.gmail.com
Backpatch-through: 14

Branch
------
REL_16_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/a38ed212ff236e4e1c94c790d9b9d18f52d2b13a

Modified Files
--------------
src/bin/pg_upgrade/dump.c       |  6 +++++-
src/bin/pg_upgrade/pg_upgrade.h |  1 +
src/bin/pg_upgrade/server.c     |  2 ++
src/bin/pg_upgrade/version.c    | 31 +++++++++++++++++++++++++++++++
4 files changed, 39 insertions(+), 1 deletion(-)



view thread (6+ messages)  latest in thread

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: [email protected]
  Cc: [email protected], [email protected]
  Subject: Re: pgsql: pg_upgrade: Use max_protocol_version=3.0 for older servers
  In-Reply-To: <[email protected]>

* 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