From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Fix pg_upgrade around multixid and mxoff wraparound
Date: Wed, 12 Nov 2025 11:13:18 +0000
Message-ID: <E1vJ8ms-006E34-05@gemulon.postgresql.org> (raw)
Fix pg_upgrade around multixid and mxoff wraparound
pg_resetwal didn't accept multixid 0 or multixact offset UINT32_MAX,
but they are both valid values that can appear in the control file.
That caused pg_upgrade to fail if you tried to upgrade a cluster
exactly at multixid or offset wraparound, because pg_upgrade calls
pg_resetwal to restore multixid/offset on the new cluster to the
values from the old cluster. To fix, allow those values in
pg_resetwal.
Fixes bugs #18863 and #18865 reported by Dmitry Kovalenko.
Backpatch down to v15. Version 14 has the same bug, but the patch
doesn't apply cleanly there. It could be made to work but it doesn't
seem worth the effort given how rare it is to hit this problem with
pg_upgrade, and how few people are upgrading to v14 anymore.
Author: Maxim Orlov <orlovmg@gmail.com>
Discussion: https://www.postgresql.org/message-id/CACG%3DezaApSMTjd%3DM2Sfn5Ucuggd3FG8Z8Qte8Xq9k5-%2BRQis-g@mail...
Discussion: https://www.postgresql.org/message-id/18863-72f08858855344a2@postgresql.org
Discussion: https://www.postgresql.org/message-id/18865-d4c66cf35c2a67af@postgresql.org
Backpatch-through: 15
Branch
------
REL_15_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/97cd4b65af6c71b31a9c08f5838c6cdd58c1866c
Modified Files
--------------
src/bin/pg_resetwal/pg_resetwal.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: heikki.linnakangas@iki.fi, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Fix pg_upgrade around multixid and mxoff wraparound
In-Reply-To: <E1vJ8ms-006E34-05@gemulon.postgresql.org>
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