Date: Tue, 23 Mar 2021 14:30:33 -0400
From: Bruce Momjian <bruce@momjian.us>
To: "Bossart, Nathan" <bossartn@amazon.com>
Cc: Stephen Frost <sfrost@snowman.net>,
	Michael Paquier <michael@paquier.xyz>,
	David Steele <david@pgmasters.net>,
	Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
	Alvaro Herrera <alvherre@alvh.no-ip.org>,
	Laurenz Albe <laurenz.albe@cybertec.at>,
	Bernd Helmle <mailings@oopsware.de>,
	"tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>,
	Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: Change default of checkpoint_completion_target
Message-ID: <20210323183033.GI579@momjian.us>
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On Tue, Mar 23, 2021 at 06:24:07PM +0000, Bossart, Nathan wrote:
> LGTM.  I just have a few small wording suggestions.
> 
> +        completion overhead.  Reducing this parameter is not recommended as that
> +        causes the I/O from the checkpoint to have to complete faster, resulting
> +        in a higher I/O rate, while then having a period of less I/O between the
> +        completion of the checkpoint and the start of the next scheduled
> +        checkpoint.  This parameter can only be set in the
> 
> Reducing this parameter is not recommended because it forces the
> checkpoint to complete faster.  This results in a higher rate of I/O
> during the checkpoint followed by a period of less I/O between
> checkpoint completion and the next scheduled checkpoint.

FYI, I am very happy this issue is being addressed for PG 14.  :-)

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  If only the physical world exists, free will is an illusion.