Re: pgsql: libpq: Grease the protocol by default - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: pgsql: libpq: Grease the protocol by default
Date
Msg-id ebe65134-a062-4e85-b7be-387f29ea3836@dunslane.net
Whole thread Raw
In response to Re: pgsql: libpq: Grease the protocol by default  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: pgsql: libpq: Grease the protocol by default
List pgsql-hackers


On 2026-02-23 Mo 9:08 PM, Tom Lane wrote:
Jacob Champion <jacob.champion@enterprisedb.com> writes:
On Mon, Feb 23, 2026 at 4:45 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Also: I was initially baffled why you thought this needs
back-patching, but I guess you have one eye on packagers like
Debian who think they can make older versions use newer libpq.so.
Right.
Actually, that is going to be harder than you thought, because libpq
before v18 will spit up on connection option "max_protocol_version".
This patch will not work as-is for back-patching unless we care to
also back-patch the addition of that option, which I'd be inclined
to resist.

Fortunately, we long ago had the foresight to invent PQlibVersion,
so you could make addition of the extra option conditional on
PQlibVersion(conn) >= 180000 in branches before 18.

Hmmm, looks like the -dump1.log output is actually from *before*
pg_upgrade actually runs:
Yeah, I came to the same conclusion.  I got a clean BF run using
your patch together with the attached patch for the BF client.
(In this patch, I did not worry about scenarios involving old
minor releases.  If Andrew is excited about that case he can
extend the version-comparison logic.)
			


I am not worried about old minor releases. I am currently testing a patch with similar intent to yours.


cheers


andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com

pgsql-hackers by date:

Previous
From: Fujii Masao
Date:
Subject: Re: Fix bug of clearing of waitStart in ProcWakeup()
Next
From: Andrew Dunstan
Date:
Subject: Re: getting "shell command argument contains a newline or carriage return:" error with pg_dumpall when db name have new line in double quote