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Re: Working on huge RAM based datasets

From: "Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com>
To: "Jan Wieck" <JanWieck(at)Yahoo(dot)com>
Cc: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Working on huge RAM based datasets
Date: 2004-07-12 14:05:06
Message-ID: 6EE64EF3AB31D5448D0007DD34EEB34101AEC9@Herge.rcsinc.local (view raw or flat)
Thread:
Lists: pgsql-performance
Jan wrote:
> > The disk cache on most operating systems is optimized.  Plus,
keeping
> > shared buffers low gives you more room to bump up the sort memory,
which
> > will make your big queries run faster.
> 
> Plus, the situation will change dramatically with 7.5 where the disk
> cache will have less information than the PG shared buffers, which
will
> become sequential scan resistant and will know that a block was pulled
> in on behalf of vacuum and not because the regular database access
> pattern required it.

Hm. In my experience the different between data cached between shared
buffers and the O/S is not very much...both are fast.  However, I almost
always see dramatic performance speedups for bumping up work mem.  Are
you suggesting that it will be advantageous to bump up shared buffers?

Merlin



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Subject: Re: Working on huge RAM based datasets
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