Date: Fri, 27 May 2022 12:56:47 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: =?utf-8?B?5b6Q5b+X5a6H5b6Q?= <xuzhiyuster@gmail.com>
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: How to monitor Postgres real memory usage
Message-ID: <20220527175647.GG19626@telsasoft.com>
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On Sat, May 28, 2022 at 01:40:14AM +0800, 徐志宇徐 wrote:
> vm.swappiness=0

I think this is related to the problem.

swappiness=0 means to *never* use swap, even if that means that processes are
killed.

If you really wanted that, you should remove the swap space.

Swap is extremely slow and worth avoiding, but this doesn't let you use it at
all.  You can't even look at your swap usage as a diagnostic measure to tell if
things had been paged out at some point.

I *suspect* the problem will go away if you set swappiness=1 in /proc (and in
sysctl.conf).

-- 
Justin