From owner-freebsd-amd64@FreeBSD.ORG Tue May 24 14:14:48 2005 Return-Path: X-Original-To: freebsd-amd64@freebsd.org Delivered-To: freebsd-amd64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 66F6016A41F; Tue, 24 May 2005 14:14:48 +0000 (GMT) (envelope-from vivek@khera.org) Received: from yertle.kcilink.com (yertle.kcilink.com [65.205.34.180]) by mx1.FreeBSD.org (Postfix) with ESMTP id 33F5E43D58; Tue, 24 May 2005 14:14:48 +0000 (GMT) (envelope-from vivek@khera.org) Received: from [192.168.7.103] (host-103.int.kcilink.com [192.168.7.103]) by yertle.kcilink.com (Postfix) with ESMTP id C5A08B878; Tue, 24 May 2005 10:14:47 -0400 (EDT) In-Reply-To: <20050523232948.GJ959@funkthat.com> References: <1116860293.10083.43.camel@lanshark.dmv.com> <20050523174415.GI959@funkthat.com> <1F46458B-2524-42AB-8B3D-0F54F485241B@khera.org> <20050523232948.GJ959@funkthat.com> Mime-Version: 1.0 (Apple Message framework v730) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Content-Transfer-Encoding: 7bit From: Vivek Khera Date: Tue, 24 May 2005 10:14:47 -0400 To: freebsd-amd64@freebsd.org X-Mailer: Apple Mail (2.730) Cc: freebsd-stable@freebsd.org Subject: Re: Manipulating disk cache (buf) settings X-BeenThere: freebsd-amd64@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to the AMD64 platform List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 May 2005 14:14:48 -0000 On May 23, 2005, at 7:29 PM, John-Mark Gurney wrote: > Vivek Khera wrote this message on Mon, May 23, 2005 at 17:17 -0400: >> >> Cool... So what would you recommend telling an application like >> Postgres what the cache size is? All of RAM? That seems unlikely >> given much of the ram is used for other things. Is there no upper >> bound in how much RAM will be used for the cache? >> > > I'm not familar host Postgres uses the cache number to change it's > behavior, but I would say choose a responable amount of memory that > you expect to regularly have available on the system... If you are > only using it for db, and a few other small processes, 512meg less > than ram is probably reasonable... Thanks. Since PG also uses a bunch of RAM for internal ops like sorting and such, I suspect telling it that 50% of RAM is available for cache will be good. Testing theory now... :-) Vivek Khera, Ph.D. +1-301-869-4449 x806