Received: from localhost (unknown [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id ABD6F2E00B6 for ; Fri, 15 Feb 2008 08:35:40 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 22450-04 for ; Fri, 15 Feb 2008 08:35:26 -0400 (AST) Received: from hyperion.scode.org (hyperion.scode.org [85.17.42.115]) by postgresql.org (Postfix) with ESMTP id CA4F52E00A8 for ; Fri, 15 Feb 2008 08:35:32 -0400 (AST) Received: by hyperion.scode.org (Postfix, from userid 1001) id 5D38F23C489; Fri, 15 Feb 2008 13:35:29 +0100 (CET) Date: Fri, 15 Feb 2008 13:35:29 +0100 From: Peter Schuller To: pgsql-performance@postgresql.org Subject: shared_buffers in 8.3 w/ lots of RAM on dedicated PG machine Message-ID: <20080215123528.GA16532@hyperion.scode.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="HlL+5n6rz5pIUxbD" Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200802/176 X-Sequence-Number: 28718 --HlL+5n6rz5pIUxbD Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello, my impression has been that in the past, there has been a general semi-consensus that upping shared_buffers to use the majority of RAM has not generally been recommended, with reliance on the buffer cache instead being the recommendation. Given the changes that have gone into 8.3, in particular with regards to minimizing the impact of large sequential scans, would it be correct to say that given that - enough memory is left for other PG bits (sort mems and whatnot else) - only PG is running on the machine - you're on 64 bit so do not run into address space issues - the database working set is larger than RAM it would be generally advisable to pump up shared_buffers pretty much as far as possible instead of relying on the buffer cache? --=20 / Peter Schuller PGP userID: 0xE9758B7D or 'Peter Schuller ' Key retrieval: Send an E-Mail to getpgpkey@scode.org E-Mail: peter.schuller@infidyne.com Web: http://www.scode.org --HlL+5n6rz5pIUxbD Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQFHtYcQDNor2+l1i30RAruoAKCaGMctnObKM4qcE8ROh/aDhbZAVACeOr1H BO/lEZK2+IoNesY0qb5AkTw= =rEqN -----END PGP SIGNATURE----- --HlL+5n6rz5pIUxbD--