From owner-freebsd-hackers Fri Mar 20 14:03:02 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id OAA06238 for freebsd-hackers-outgoing; Fri, 20 Mar 1998 14:03:02 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from sendero.simon-shapiro.org (sendero-fddi.Simon-Shapiro.ORG [206.190.148.2]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id OAA06039 for ; Fri, 20 Mar 1998 14:02:14 -0800 (PST) (envelope-from shimon@simon-shapiro.org) Received: (qmail 28203 invoked from network); 20 Mar 1998 22:07:54 -0000 Received: from localhost.simon-shapiro.org (HELO sendero-fxp0.simon-shapiro.org) (@127.0.0.1) by localhost.simon-shapiro.org with SMTP; 20 Mar 1998 22:07:54 -0000 Message-ID: X-Mailer: XFMail 1.3-alpha-031798 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <19980320221931.51710@follo.net> Date: Fri, 20 Mar 1998 14:07:54 -0800 (PST) Reply-To: shimon@simon-shapiro.org Organization: The Simon Shapiro Foundation From: Simon Shapiro To: Eivind Eklund Subject: Re: How do you increase available SYSV shared memory? Cc: roberto@keltia.freenix.fr, freebsd-hackers@FreeBSD.ORG, "Kent S. Gordon" Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 20-Mar-98 Eivind Eklund wrote: > On Fri, Mar 20, 1998 at 12:32:19PM -0800, Simon Shapiro wrote: >> >> On 18-Mar-98 Kent S. Gordon wrote: >> > >> >>>>>> "shimon" == Simon Shapiro writes: >> > I have been thinking of changing Postgres to use mmapped files instead >> > of SYSV shared memory. I think this should allow for larger postgres >> >> This will be a disaster. It assumes that PostgreSQL uses files for data >> storage. While this is the default mode, it is NOT the only storage >> meanager. In PostgreSQL, like most true RDBMS, the storage of data is >> decoupled from the logic of the relational model, etc. I am building a >> storage manager that uses a totally different (distributed) storage >> model >> than Unix files. A memory based storage manager already exists in >> PostgreSQL. Please do not break these. > > I don't think you're quite getting him (or I'm not getting you at all). > mmap()ing /dev/zero is a common way of getting hold of shared memory, > instead of using the SYSV SHMEM extension. mmap'ing usually works > better. > > This is just replacing one technique for getting hold of shared memory > with > another; it does nothing to the storage manager. Apologies then. I thought the intention was to mmap the storage manager. I am still recovering from a nasty cold and an all-night flight back home. The trip was worht it, though :-) ---------- Sincerely Yours, Simon Shapiro Shimon@Simon-Shapiro.ORG Voice: 503.799.2313 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message