Date: Fri, 7 Jan 2022 16:52:56 -0500
From: Bruce Momjian <bruce@momjian.us>
To: Mathias Kunter <mathiaskunter@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-docs@lists.postgresql.org
Subject: Re: random_page_cost configuration parameter
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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.