Horton

Re: Safe vm.overcommit_ratio for Large Multi-Instance PostgreSQL Fleet

Frédéric Yhuel <frederic.yhuel@dalibo.com>

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From: Frédéric Yhuel <frederic.yhuel@dalibo.com>
To: Frits Hoogland <frits.hoogland@gmail.com>
Cc: Joe Conway <mail@joeconway.com>, Priya V <mailme0216@gmail.com>, pgsql-performance@lists.postgresql.org
Date: 2025-08-19T17:40:10Z
Lists: pgsql-performance 

On 8/19/25 17:37, Frits Hoogland wrote:
> The specific issue I see in certain cases leading to unreasonable swap usage is Linux workingset detection kicking in

Do you have a way to highlight that precisely? I mean, can you prove 
that it is Linux workingset detection that is causing swapping? I've 
also encountered surprising cases where the swap fills up despite there 
being plenty of available memory (lots of page cache). However these 
cases were not associated with slowdowns or other problems. I only 
became aware of them because a client was anxious about her swap usage.