On Mon, Feb 23, 2026 at 6:08 PM Tom Lane <[email protected]> wrote: > Jacob Champion <[email protected]> writes: > > On Mon, Feb 23, 2026 at 4:45 PM Tom Lane <[email protected]> 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".
Ha, right. Luckily the failure is very loud when testing :) > 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. Attached is a sample backport for REL_14_STABLE, using that strategy. Tested with pg_upgrade 9.2-to-14, when linked against both 14.22 and HEAD versions of libpq. I still need to run a sanity check with the other 9.x lines to make sure I've selected the right cutoffs. > 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. Nice, thanks! --Jacob
0001-pg_upgrade-Use-max_protocol_version-3.0-for-older-se.14.patch
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