Message-ID: <2c9d3664ff7adc506191f92db031543925abe0df.camel@crunchydata.com>
Subject: Re: [DOC] Add detail regarding resource consumption wrt
 max_connections
From: reid.thompson@crunchydata.com
To: Roberto Mello <roberto.mello@gmail.com>, Cary Huang
 <cary.huang@highgo.ca>
Cc: pgsql-hackers@lists.postgresql.org
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Date: Mon, 22 Jan 2024 08:58:23 -0500
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On Fri, 2024-01-19 at 17:37 -0500, reid.thompson@crunchydata.com wrote:
> On Sat, 2024-01-13 at 10:31 -0700, Roberto Mello wrote:
> >=20
> > I can add a suggestion for the user to consider increasing
> > shared_buffers in accordance with higher max_connections, but it
> > would be better if there was a "rule of thumb" guideline to go
> > along. I'm open to suggestions.
> >=20
> > I can revise with a similar warning in max_prepared_xacts as well.
> >=20
> > Sincerely,
> >=20
> > Roberto
>=20
> Can a "close enough" rule of thumb be calculated from:
> postgresql.conf -> log_min_messages =3D debug3
>=20
> start postgresql with varying max_connections to get
> CreateSharedMemoryAndSemaphores() sizes to generate a rough equation
>=20

or maybe it would be sufficient to advise to set log_min_messages =3D
debug3 on a test DB and start/stop it with varying values of
max_connections and look at the=C2=A0differing values in=20
DEBUG: invoking IpcMemoryCreate(size=3D...) log messages for themselves.