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Re: Help Me Understand Why I'm Getting a Bad Query Plan

From: Bryan Murphy <bmurphy1976(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Help Me Understand Why I'm Getting a Bad Query Plan
Date: 2009-03-26 04:00:25
Message-ID: 7fd310d10903252100n3ba13c9fuf4818a66cf7afb10@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Wed, Mar 25, 2009 at 10:28 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Bryan Murphy <bmurphy1976(at)gmail(dot)com> writes:
>> What I did was change seq_page_cost back to 1.0 and then changed
>> random_page_cost to 0.5
>
> [ squint... ]  It makes no physical sense for random_page_cost to be
> less than seq_page_cost.  Please set them the same.
>
>                        regards, tom lane

Done.  Just  saw the tip in the docs as well.  Both are set to 0.5 now
and I'm still getting the good query plan.

Thanks!
Bryan

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