Date: Wed, 25 Oct 2006 22:34:48 -0500
From: "Jim C. Nasby" <jim@nasby.net>
To: Worky Workerson <worky.workerson@gmail.com>
Cc: Merlin Moncure <mmoncure@gmail.com>, Markus Schaber <schabi@logix-tt.com>,
	pgsql-performance@postgresql.org
Subject: Re: Best COPY Performance
Message-ID: <20061026033448.GC26892@nasby.net>
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On Wed, Oct 25, 2006 at 11:25:01AM -0400, Worky Workerson wrote:
> >I'm guessing the high bursts are checkpoints.  Can you check your log
> >files for pg and see if you are getting warnings about checkpoint
> >frequency?   You can get some mileage here by increasing wal files.
> 
> Nope, nothing in the log.  I have set:
> wal_buffers=128
> checkpoint_segments=128
> checkpoint_timeout=3000
> which I thought was rather generous.  Perhaps I should set it even
> higher for the loads?

But depending on your shared_buffer and bgwriter settings (as well as
how much WAL traffic you're generating, you could still end up with big
slugs of work to be done when checkpoints happen.

If you set checkpoint_warning to 3001, you'll see exactly when
checkpoints are happening, so you can determine if that's an issue.
-- 
Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)