From: alvherre@alvh.no-ip.org <alvherre@alvh.no-ip.org>
To: Bossart, Nathan <bossartn@amazon.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: x4mmm@yandex-team.ru <x4mmm@yandex-team.ru>
Cc: a.lubennikova@postgrespro.ru <a.lubennikova@postgrespro.ru>
Cc: hlinnaka@iki.fi <hlinnaka@iki.fi>
Cc: matsumura.ryo@fujitsu.com <matsumura.ryo@fujitsu.com>
Cc: masao.fujii@gmail.com <masao.fujii@gmail.com>
Cc: pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Re: archive status ".ready" files may be created too early
Date: Wed, 18 Aug 2021 13:04:11 -0400
Message-ID: <202108181704.y3xssxde4qsf@alvherre.pgsql> (raw)
In-Reply-To: <202108172232.nqewuhgxhxty@alvherre.pgsql>
On 2021-Aug-17, alvherre@alvh.no-ip.org wrote:
> However, why do it in a WAL-producing client-connected backend? It
> strikes me as a bad thing to do, because you are possibly causing delays
> for client-connected backends. I suggest that we should give this task
> to the WAL writer process -- say, have XLogBackgroundFlush do it.
Reading the comments on walwriter.c I am hesitant of having walwriter do
it:
> * Because the walwriter's cycle is directly linked to the maximum delay
> * before async-commit transactions are guaranteed committed, it's probably
> * unwise to load additional functionality onto it. For instance, if you've
> * got a yen to create xlog segments further in advance, that'd be better done
> * in bgwriter than in walwriter.
So that comment suggests that we should give the responsibility to bgwriter.
This seems good enough to me. I suppose if bgwriter has a long run of
buffers to write it could take a little bit of time (a few hundred
milliseconds?) but I think that should be okay.
--
Álvaro Herrera 39°49'30"S 73°17'W — https://www.EnterpriseDB.com/
"No renuncies a nada. No te aferres a nada."
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To: pgsql-hackers@postgresql.org
Cc: alvherre@alvh.no-ip.org, bossartn@amazon.com, horikyota.ntt@gmail.com, x4mmm@yandex-team.ru, a.lubennikova@postgrespro.ru, hlinnaka@iki.fi, matsumura.ryo@fujitsu.com, masao.fujii@gmail.com
Subject: Re: archive status ".ready" files may be created too early
In-Reply-To: <202108181704.y3xssxde4qsf@alvherre.pgsql>
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