From: Greg Smith <greg@2ndQuadrant.com>
To: pgsql-performance@postgresql.org
Subject: Re: raid array seek performance
Date: Wed, 14 Sep 2011 03:44:53 -0400
Message-ID: <4E705B75.8040502@2ndQuadrant.com> (raw)
In-Reply-To: <CAEV0TzAT0rJ2rWdpkwavVQBsvt9gf-EqVn9Fh9Ee2H-rArDm+Q@mail.gmail.com>
References: <CAEV0TzAT0rJ2rWdpkwavVQBsvt9gf-EqVn9Fh9Ee2H-rArDm+Q@mail.gmail.com>
On 09/13/2011 03:13 PM, Samuel Gendler wrote:
> Bonnie++ delivered the expected huge throughput for sequential read
> and write. It seems in line with other benchmarks I found online.
> However, we are only seeing 180 seeks/sec, but seems quite low.
I wouldn't worry about that if the sequential rates are good. The
bonnie++ seeks test has been giving me increasingly useless results
recently on modern hardware. And bonnie++ 1.96 continues to give me
enough weird values that I'm still using 1.03e as my standard version.
If you want to get a useful measurement of seeks/second, setup
pgbench-tools with a SELECT-only test, and create a database that's 2 to
4X as big as RAM. The TPS result you get from that is a much more
useful number for real-world seeks than this.
I'm working on a tool to directly benchmark seek performance in a way
that's useful for what people really want to know nowadays. That's
going live to the world at the end of the month, at #PgWest:
http://pgwest2011.sched.org/event/875b87d8d237bef3a53ab27ac9c8057c
--
Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
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To: pgsql-performance@postgresql.org
Cc: greg@2ndQuadrant.com
Subject: Re: raid array seek performance
In-Reply-To: <4E705B75.8040502@2ndQuadrant.com>
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