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Re: Inconsistent performance

From: Jeff <threshar(at)torgo(dot)978(dot)org>
To: Joseph Bove <jbove(at)vetstar(dot)com>
Cc: "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Inconsistent performance
Date: 2003-09-16 15:38:12
Message-ID: Pine.BSF.4.44.0309161135420.2465-100000@torgo.978.org (view raw or flat)
Thread:
Lists: pgsql-performance
On Tue, 16 Sep 2003, Joseph Bove wrote:

> I still think that 3 seconds is not acceptable. However, I reserve the
> right to be wrong. Does it sound unrealistic to expect PostgreSQL to be
> able to read 90,000 rows with 300 bytes per row in under a second?
>
first, check to see what your max throughput on your disk is using a
benchmark such as Bonnie (Making sure to use a size LARGER than phsyical
memory. 2x physical is veyr optimial).

next, run your query again with a vmstat 1 running in another term.

See how close the vmstat "bi" numbers correspond to your max according to
bonnie.  You could have an IO bottleneck.  (I once went running around
trying to figure it out and then discovered the issue was IO).



--
Jeff Trout <jeff(at)jefftrout(dot)com>
http://www.jefftrout.com/
http://www.stuarthamm.net/



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