Date: Fri, 15 Jul 2022 09:45:40 +0200
From: hubert depesz lubaczewski <depesz@depesz.com>
Sender: depesz@depesz.com
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: Excessive number of replication slots for 12->14 logical
 replication
Message-ID: <20220715074540.GA26521@depesz.com>
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On Fri, Jul 15, 2022 at 01:55:32PM +0900, Kyotaro Horiguchi wrote:
> Thus, not just about logical replication, some spare slots are
> necessary to keep things running smoothly.  I guess that it is
> widely(?)  recommended to provide at least one or two spare slots to
> allow replication reconnection in case of silent disconnections, but I
> haven't found something like that in the documentation.. In your case,
> it seems to me larger number of spare slots makes the server run more
> smoothly, *I* don't think 10 spare slots affect anything badly.

OK. The explanation makes sense, but leads to problem - we have 50
max replication slots, which gives me 20 spare slots.

And I'm not sure how much should I increase it so that it will still
work.

Plus - there is the problem that increasing max_replication_slots
requires restart :(

Anyway, will deal with it, now that I understand the issue. Thanks
a lot.

Best regards,

depesz