From: Luke Lonergan <llonergan@greenplum.com>
To: Merlin Moncure <mmoncure@gmail.com>
To: Worky Workerson <worky.workerson@gmail.com>
Cc: Markus Schaber <schabi@logix-tt.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Best COPY Performance
Date: Wed, 25 Oct 2006 09:34:01 -0700
Message-ID: <C164E009.51ED%llonergan@greenplum.com> (raw)
In-Reply-To: <b42b73150610250838g7e1cb6ccl30156787343bc79c@mail.gmail.com>
Merlin,
On 10/25/06 8:38 AM, "Merlin Moncure" <mmoncure@gmail.com> wrote:
> in theory, with 10 10k disks in raid 10, you should be able to keep
> your 2fc link saturated all the time unless your i/o is extremely
> random. random i/o is the wild card here, ideally you should see at
> least 2000 seeks in bonnie...lets see what comes up.
The 2000 seeks/sec are irrelevant to Postgres with one user doing COPY.
Because the I/O is single threaded, you will get one disk worth of seeks for
one user, roughly 150/second on a 10K RPM drive.
I suspect the problem here is the sequential I/O rate - let's wait and see
what the dd test results look like.
- Luke
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To: pgsql-performance@postgresql.org
Cc: llonergan@greenplum.com, mmoncure@gmail.com, worky.workerson@gmail.com, schabi@logix-tt.com
Subject: Re: Best COPY Performance
In-Reply-To: <C164E009.51ED%llonergan@greenplum.com>
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