From: Georg H. <georg-h@silentrunner.de>
To: vas@sibptus.ru
To: pgsql-admin@lists.postgresql.org
Subject: Re: Temporary disabling a replica in a Patroni cluster
Date: Fri, 25 Aug 2023 13:24:12 +0200
Message-ID: <aa042283-01b1-36f1-3d1e-90fbb5dd6a75@silentrunner.de> (raw)
In-Reply-To: <ZOiOEgeQ0HywK9sN@admin.sibptus.ru>
References: <ZOiOEgeQ0HywK9sN@admin.sibptus.ru>
Hello Victor,
Am 25.08.2023 um 13:18 schrieb Victor Sudakov:
> Dear Colleagues,
>
> Do you perchance know what is the correct procedure of temporarily
> taking down a replica in a Patroni cluster, e.g. for 5-10 minutes of
> hardware maintenance?
>
> The problem is that after stopping the patroni process (service) on a
> replica, patroni removes the corresponding physical replication slot
> from the leader, and unless the wal_keep_size value is unsanely high,
> the replica, when up again, cannot restart streaming because the WAL
> segments are already gone from the leader.
>
> Well, you all know:
> <%%%>LOG: started streaming WAL from primary at B4A0/E2000000 on timeline 8
> <%%%>FATAL: could not receive data from WAL stream: ERROR: requested WAL segment 000000080000B4A0000000E2 has already been removed
> <%%%>LOG: waiting for WAL to become available at B4A0/E2002000
>
> Do you think there is a way to tell Patroni that a replica is down
> temporarily and its replication slot should not be removed?
>
> Or, what am I missing?
you may use patronictl pause + resume
keep in mind to set wal_keep_size (or wal_keep_segments depending on
your PG version high enough)
regards
Georg
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: pgsql-admin@postgresql.org
Cc: georg-h@silentrunner.de, vas@sibptus.ru, pgsql-admin@lists.postgresql.org
Subject: Re: Temporary disabling a replica in a Patroni cluster
In-Reply-To: <aa042283-01b1-36f1-3d1e-90fbb5dd6a75@silentrunner.de>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox