On Fri, Dec 18, 2009 at 11:37 PM, Alex - <aintokyo@hotmail.com> wrote:
> Hmm...
> how can that be. This is happening every day, so its not a one off or
> happens once in the morning then in the afternoon. There is also no other
> task running on the system, its dedicated to postgres.
> Could the Autovacuum cause problems? Starting to invoke Analyze at the
> beginning of the day but the keep silent till the day timestamp breaks ?
> The think is that I have 4 servers setup in a similar way and all have
> exactly the same problem.
What cron jobs are on that machine that run at night? Note that on
many OSes, maintenance crons are scheduled in a dir something like
/etc/cron.daily etc... On my laptop they all run at midnight. I'm
wondering if they're blowing out your cache so that you just don't
have the same performance the first time you hit a particular dataset
after they've run. Just a guess. You could try disabling them for a
day and see what happens.