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Re: reducing random_page_cost from 4 to 2 to force index scan

From: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
To: Jesper Krogh <jesper(at)krogh(dot)cc>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: reducing random_page_cost from 4 to 2 to force index scan
Date: 2011-05-16 16:45:28
Message-ID: BANLkTimw2xWYQ_Hz4vtLXx-2nZRjRfoMMw@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Sun, May 15, 2011 at 9:49 PM, Jesper Krogh <jesper(at)krogh(dot)cc> wrote:
>
> Ok, it may not work as well with index'es, since having 1% in cache may very
> well mean that 90% of all requested blocks are there.. for tables in should
> be more trivial.

Why would the index have a meaningful hot-spot unless the underlying
table had one as well?  (Of course the root block will be a hot-spot,
but certainly not 90% of all requests)

Cheers,

Jeff

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