Re: Script to compute random page cost

From: Oliver Elphick <olly(at)lfix(dot)co(dot)uk>
To: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
Cc: PostgreSQL-development <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: Script to compute random page cost
Date: 2002-09-09 11:52:38
Message-ID: 1031572358.24419.214.camel@linda
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On Mon, 2002-09-09 at 07:13, Bruce Momjian wrote:
>
> OK, turns out that the loop for sequential scan ran fewer times and was
> skewing the numbers. I have a new version at:
>
> ftp://candle.pha.pa.us/pub/postgresql/randcost
>
> I get _much_ lower numbers now for random_page_cost.
>
> ---------------------------------------------------------------------------

Five successive runs:

random_page_cost = 0.947368
random_page_cost = 0.894737
random_page_cost = 0.947368
random_page_cost = 0.894737
random_page_cost = 0.894737

linux 2.4.18 SMP
dual Athlon MP 1900+
512Mb RAM
SCSI

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight, UK
http://www.lfix.co.uk/oliver
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C
========================================
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