From: Shaun Thomas <sthomas@peak6.com>
To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
Cc: pgsql-performance@postgresql.org
Cc: Claire Chang <yenhsiac@yahoo.com>
Subject: Re: Postgres 8.4 memory related parameters
Date: Thu, 4 Aug 2011 16:02:11 -0500
Message-ID: <4E3B08D3.606@peak6.com> (raw)
In-Reply-To: <4E3ABCFB020000250003FAF4@gw.wicourts.gov>
References: <1312489633.71838.YahooMailClassic@web31912.mail.mud.yahoo.com>
<4E3ABCFB020000250003FAF4@gw.wicourts.gov>
On 08/04/2011 03:38 PM, Kevin Grittner wrote:
> You're probably going to get better performance by setting that to 2
> to 3 times the number of actual cores (don't county hyperthreading
> for this purpose), and using a connection pooler to funnel the 600
> user connections down to a smaller number of database connections.
Your note about Hyperthreading *used* to be true. I'm not sure exactly
what they did to the Intel nehalem cores, but hyperthreading actually
seems to be much better now. It's not a true multiplier, but our pgbench
scores were 40% to 60% higher with HT enabled up to at least 5x the
number of cores.
I was honestly shocked at those results, but they were consistent across
multiple machines from two separate vendors.
--
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas@peak6.com
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To: pgsql-performance@postgresql.org
Cc: sthomas@peak6.com, Kevin.Grittner@wicourts.gov, yenhsiac@yahoo.com
Subject: Re: Postgres 8.4 memory related parameters
In-Reply-To: <4E3B08D3.606@peak6.com>
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