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In-Reply-To: <20221117162431.a3kqnpgjjsa7foxy@awork3.anarazel.de>
From: Robert Haas <robertmhaas@gmail.com>
Date: Thu, 17 Nov 2022 12:21:03 -0500
Message-ID: 
 <CA+TgmoYdb2mz3NpEhohG+Th6oCmYH0o7+=Zxb6j+AZRXAN9DEg@mail.gmail.com>
Subject: Re: Report checkpoint progress with pg_stat_progress_checkpoint (was:
 Report checkpoint progress in server logs)
To: Andres Freund <andres@anarazel.de>
Cc: Melanie Plageman <melanieplageman@gmail.com>,
	Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
	"Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>,
 Nitin Jadhav <nitinjadhavpostgres@gmail.com>,
	Matthias van de Meent <boekewurm+postgres@gmail.com>,
 Ashutosh Sharma <ashu.coek88@gmail.com>,
	Julien Rouhaud <rjuju123@gmail.com>, Bruce Momjian <bruce@momjian.us>,
 Tom Lane <tgl@sss.pgh.pa.us>,
	Magnus Hagander <magnus@hagander.net>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Thu, Nov 17, 2022 at 11:24 AM Andres Freund <andres@anarazel.de> wrote:
> As an experiment, I added a progress report to BufferSync()'s first loop
> (i.e. where it checks all buffers). On a 128GB shared_buffers cluster that
> increases the time for a do-nothing checkpoint from ~235ms to ~280ms. If I
> remove the changecount stuff and use a single write + write barrier, it ends
> up as 250ms. Inlining brings it down a bit further, to 247ms.

OK, I'd say that's pretty good evidence that we can't totally
disregard the issue.

-- 
Robert Haas
EDB: http://www.enterprisedb.com