From: Bruce Momjian <bruce@momjian.us>
To: Mathias Kunter <mathiaskunter@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-docs@lists.postgresql.org
Subject: Re: random_page_cost configuration parameter
Date: Fri, 7 Jan 2022 16:52:56 -0500
Message-ID: <Ydi2OIrmRtV9fS0o@momjian.us> (raw)
In-Reply-To: <6bb6023b-fce3-801d-e799-8111cc317e35@gmail.com>
References: <9271c072-e91d-4dc5-c0a9-197f47291671@gmail.com>
<1760891.1640707405@sss.pgh.pa.us>
<6bb6023b-fce3-801d-e799-8111cc317e35@gmail.com>
On Wed, Jan 5, 2022 at 07:27:55PM +0100, Mathias Kunter wrote:
> Am 28.12.21 um 17:03 schrieb Tom Lane:
> > Mathias Kunter <mathiaskunter@gmail.com> writes:
> > > Consider the situation
> > > where the randomly fetched pages are mostly (or even entirely) cached in
> > > RAM, but where the sequentially fetched pages must be mostly read from
> > > disk. An example for such a scenario is a database system which uses
> > > RAM-cached indices.
> >
> > I think fooling with effective_cache_size is a better way to model
> > that situation.
>
> The default value of effective_cache_size is 4 GB. Which value should be
> used instead on a system which only has 4 GB of total RAM, but still uses
> RAM-cached indices?
This might help:
https://momjian.us/main/blogs/pgblog/2012.html#May_4_2012
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
If only the physical world exists, free will is an illusion.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-docs@postgresql.org
Cc: bruce@momjian.us, mathiaskunter@gmail.com, tgl@sss.pgh.pa.us, pgsql-docs@lists.postgresql.org
Subject: Re: random_page_cost configuration parameter
In-Reply-To: <Ydi2OIrmRtV9fS0o@momjian.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox