From: Luke Lonergan <llonergan@greenplum.com>
To: stange@rentec.com
Cc: Postgresql Performance <pgsql-performance@postgresql.org>
Subject: Re: Hardware/OS recommendations for large databases (
Date: Wed, 23 Nov 2005 17:50:57 -0800
Message-ID: <BFAA5C81.145DB%llonergan@greenplum.com> (raw)
In-Reply-To: <4384E685.4060108@rentec.com>
Alan,
On 11/23/05 2:00 PM, "Alan Stange" <stange@rentec.com> wrote:
> Luke Lonergan wrote:
>> Why not contribute something - put up proof of your stated 8KB versus
>> 32KB page size improvement.
>
> I did observe that 32KB block sizes were a significant win "for our
> usage patterns". It might be a win for any of the following reasons:
> (* big snip *)
Though all of what you relate is interesting, it seems irrelevant to your
earlier statement here:
>> Alan Stange <stange@rentec.com> writes:
>> If your goal is sequential IO, then one must use larger block sizes.
>> No one would use 8KB IO for achieving high sequential IO rates. Simply
>> put, read() is about the slowest way to get 8KB of data. Switching
>> to 32KB blocks reduces all the system call overhead by a large margin.
>> Larger blocks would be better still, up to the stripe size of your
>> mirror. (Of course, you're using a mirror and not raid5 if you care
>> about performance.)
And I am interested in seeing if your statement is correct. Do you have any
proof of this to share?
- Luke
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To: pgsql-performance@postgresql.org
Cc: llonergan@greenplum.com, stange@rentec.com
Subject: Re: Hardware/OS recommendations for large databases (
In-Reply-To: <BFAA5C81.145DB%llonergan@greenplum.com>
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