Re: Huge number of disk writes after migration to 8.1

From: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
To: Chris Campbell <chris(at)bignerdranch(dot)com>
Cc: pgsql-bugs(at)postgreSQL(dot)org
Subject: Re: Huge number of disk writes after migration to 8.1
Date: 2006-01-19 13:51:18
Message-ID: 20060119135118.GA27204@surnet.cl
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Chris Campbell wrote:
> On Jan 19, 2006, at 06:51, Magnus Hagander wrote:
>
> >In most cases you're going to see extremely few reads compared to
> >writes
> >on pg_stats, right? So why not have the backends connect to the stats
> >process (or perhaps use UDP, or use the pipe, or whatever) and
> >fetch the
> >data when needed. So when nobody fetches any data, there is no
> >overhead
> >(except for the stats process adding up values, of course).
>
> Do the stats need to persist across postmaster restarts (or crashes)?

After a crash we forcibly _delete_ the stat file. OTOH, on clean
shutdown it would be quite possible to write it (which would be the only
time at which the file is written).

--
Alvaro Herrera http://www.advogato.org/person/alvherre
Licensee shall have no right to use the Licensed Software
for productive or commercial use. (Licencia de StarOffice 6.0 beta)

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