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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Christopher Petrilli <petrilli@gmail.com>
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 13:05:25 -0400
Message-ID: <7436.1121792725@sss.pgh.pa.us> (raw)
In-Reply-To: <59d991c4050719095440cd3de5@mail.gmail.com>
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	<4541.1121788647@sss.pgh.pa.us>
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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.)

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 ...

			regards, tom lane



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