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Re: Odd off-by-one dirty buffers and checkpoint buffers written - Mailing list pgsql-hackers

From Nathan Bossart
Subject Re: Odd off-by-one dirty buffers and checkpoint buffers written
Date
Msg-id 20220419233651.GA2578385@nathanxps13
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In response to Odd off-by-one dirty buffers and checkpoint buffers written  ("David G. Johnston" <david.g.johnston@gmail.com>)
Responses Re: Odd off-by-one dirty buffers and checkpoint buffers written  ("David G. Johnston" <david.g.johnston@gmail.com>)
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On Tue, Apr 19, 2022 at 04:21:21PM -0700, David G. Johnston wrote:
> I've done this four times in a row and while the number of dirty buffers
> shown each time vary (see below) I see that "wrote N buffers" is always
> exactly one more than the total count of dirty buffers.  I'm just curious
> if anyone has a quick answer for this unusual correspondence.

I see that SlruInternalWritePage() increments ckpt_bufs_written, so my
first guess would be that it's due to something like CheckPointCLOG().

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

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