Date: Mon, 18 May 2026 14:27:08 +0200
From: hubert depesz lubaczewski <depesz@depesz.com>
Sender: depesz@depesz.com
To: PostgreSQL General <pgsql-general@lists.postgresql.org>
Subject: Is there any reason why pg_walfile_name() doesn't take timeline
 change into consideration?
Message-ID: <agsFnCHnXlCoggik@depesz.com>
Reply-To: depesz@depesz.com
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Hi,
I tried on a server that is on timeline 7 now, with .history being:

1       A9/5E0000A0     no recovery target specified
2       127/EB0000A0    no recovery target specified
3       127/F40000A0    no recovery target specified
4       128/170000A0    no recovery target specified
5       188/C70000A0    no recovery target specified
6       7B8/90000A0     no recovery target specified


When I wal file that is "current", i get sensible filename:

=# select pg_walfile_name('800/123');
     pg_walfile_name
══════════════════════════
 000000070000080000000000
(1 row)

But when I try to find walfile for old lsn, from older timeline, I'm getting bad results:

=# select pg_walfile_name('125/123');
     pg_walfile_name
══════════════════════════
 000000070000012500000000
(1 row)

Timeline 7 was was "there" when wal lsn was 125/…. Is it just missing
functionality, or am I missing something more complicated?

Best regards,

depesz