From: Christopher Petrilli <petrilli@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PFC <lists@boutiquenumerique.com>
Cc: Vivek Khera <vivek@khera.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Impact of checkpoint_segments under continual load conditions
Date: Tue, 19 Jul 2005 13:13:05 -0400
Message-ID: <59d991c405071910133e28031a@mail.gmail.com> (raw)
In-Reply-To: <7436.1121792725@sss.pgh.pa.us>
References: <59d991c4050717100874c08a86@mail.gmail.com>
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<59d991c405071907482bb0689b@mail.gmail.com>
<op.st52tvunth1vuj@localhost>
<59d991c4050719084460b376f1@mail.gmail.com>
<4541.1121788647@sss.pgh.pa.us>
<59d991c40507190930244ba9bb@mail.gmail.com>
<7224.1121791328@sss.pgh.pa.us>
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<7436.1121792725@sss.pgh.pa.us>
On 7/19/05, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Christopher Petrilli <petrilli@gmail.com> writes:
> > As I'm doing this, I'm noticing something *VERY* disturbing to me:
> > postmaster backend: 20.3% CPU
> > psql frontend: 61.2% CPU
>
> > WTF? The only thing going through the front end is the COPY command,
> > and it's sent to the backend to read from a file?
>
> Are you sure the backend is reading directly from the file, and not
> through psql? (\copy, or COPY FROM STDIN, would go through psql.)
The exact command is:
COPY test (columnlist...) FROM '/tmp/loadfile';
> But even so that seems awfully high, considering how little work psql
> has to do compared to the backend. Has anyone ever profiled psql doing
> this sort of thing? I know I've spent all my time looking at the
> backend ...
Linux 2.6, ext3, data=writeback
It's flipped now (stil lrunning), and it's 48% postmaster, 36% psql,
but anything more than 1-2% seems absurd.
Chris
--
| Christopher Petrilli
| petrilli@gmail.com
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To: pgsql-performance@postgresql.org
Cc: petrilli@gmail.com, tgl@sss.pgh.pa.us, lists@boutiquenumerique.com, vivek@khera.org
Subject: Re: Impact of checkpoint_segments under continual load conditions
In-Reply-To: <59d991c405071910133e28031a@mail.gmail.com>
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