From: Klint Gore <kg@kgb.une.edu.au>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Jim C.Nasby <jnasby@pervasive.com>
Cc: pgsql-performance@postgresql.org, Jeffrey Tenny <jeffrey.tenny@comcast.net>
Subject: Re: performance question (something to do w/ parameterized
Date: Tue, 09 May 2006 10:10:19 +1000
Message-ID: <445FDDEB225.3451KG@129.180.47.120> (raw)
In-Reply-To: <2731.1147131457@sss.pgh.pa.us>
References: <445FD5B3.1010708@comcast.net>
<2731.1147131457@sss.pgh.pa.us>
On Mon, 08 May 2006 19:37:37 -0400, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Jeffrey Tenny <jeffrey.tenny@comcast.net> writes:
> > The server was already running with random_page_cost=2 today for all tests, because of
> > the mods I've made to improve other problem queries in the past (my settings noted below, and
> > before in another msg on this topic).
>
> > So to nail this particular query something additional is required (even lower random_page_cost?).
> > What's a good value for slower processors/memory and database in memory?
>
> If you're pretty sure the database will always be RAM-resident, then 1.0
> is the theoretically correct value.
Would it be possible to craft a set of queries on specific data that
could advise a reasonable value for random_page_cost?
What sort of data distribution and query type would be heavily dependant
on random_page_cost? i.e. randomness of the data, size of the data
compared to physical memory.
klint.
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To: pgsql-performance@postgresql.org
Cc: kg@kgb.une.edu.au, tgl@sss.pgh.pa.us, jnasby@pervasive.com, jeffrey.tenny@comcast.net
Subject: Re: performance question (something to do w/ parameterized
In-Reply-To: <445FDDEB225.3451KG@129.180.47.120>
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