Message-ID: <03763b6b43cfd8a7194c2fb06452178db4256494.camel@cybertec.at>
Subject: Re: Another documentation issue
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Igor Korot <ikorot01@gmail.com>, "pgsql-generallists.postgresql.org"
	 <pgsql-general@lists.postgresql.org>
Date: Wed, 23 Apr 2025 09:16:23 +0200
In-Reply-To: <CA+FnnTxPHoCZz2JBFxC3Wdsce9KUwNL0KcH5Ua37R55XLQbrpg@mail.gmail.com>
References: 
	<CA+FnnTxPHoCZz2JBFxC3Wdsce9KUwNL0KcH5Ua37R55XLQbrpg@mail.gmail.com>
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On Wed, 2025-04-23 at 00:21 -0500, Igor Korot wrote:
> On the page https://www.postgresql.org/docs/current/runtime-config-query.=
html#GUC-SEQ-PAGE-COST
>=20
> it is only given the default value of this parameter.
>=20
> No min/max values are provided..
>=20
> The same can be sad about
> https://www.postgresql.org/docs/current/runtime-config-query.html#GUC-RAN=
DOM-PAGE-COST

Sad.  But you can interpret it as "there is no maximum".  The actual maximu=
m is DBL_MAX,
the biggest double precision value that your system can handle, and may dep=
end on your
architecture.

> However, this page
> https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-=
EFFECTIVE-IO-CONCURRENCY
> describes both default and mn/max, however t s says:
>=20
> [quote]
> The default is 1 on supported systems, otherwise 0
> [/quote]]
>=20
> No explanation of what is "supported system" is given...
>=20
> And the same can be said about
> https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-=
MAINTENANCE-IO-CONCURRENCY.

According to the source, it is "systems that have posix_fadvise()".  We cou=
ld document that,
but I don't know if it would help many people.  I am not sure how easy and =
feasible it is
to research which versions of which operating systems qualify.

Yours,
Laurenz Albe