From owner-freebsd-hackers Tue Mar 24 07:57:37 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id HAA13150 for freebsd-hackers-outgoing; Tue, 24 Mar 1998 07:57:37 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from soccer.inetspace.com (soccer.inetspace.com [206.50.163.48]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id HAA13144 for ; Tue, 24 Mar 1998 07:57:33 -0800 (PST) (envelope-from kgor@soccer.inetspace.com) Received: (from kgor@localhost) by soccer.inetspace.com (8.8.7/8.8.7) id JAA24709; Tue, 24 Mar 1998 09:57:05 -0600 (CST) (envelope-from kgor) Date: Tue, 24 Mar 1998 09:57:05 -0600 (CST) Message-Id: <199803241557.JAA24709@soccer.inetspace.com> From: "Kent S. Gordon" To: eivind@yes.no CC: shimon@simon-shapiro.org, roberto@keltia.freenix.fr, freebsd-hackers@FreeBSD.ORG In-reply-to: <19980320221931.51710@follo.net> (message from Eivind Eklund on Fri, 20 Mar 1998 22:19:31 +0100) Subject: Re: How do you increase available SYSV shared memory? Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >>>>> "eivind" == Eivind Eklund writes: > 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 am not going to change any of the storage manager code. > 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. I probably will not be using /dev/zero, but yes I am just replacing one method of getting shared memory with another way. It looks like it will only impact less than 50 lines of postgres code. > This is just replacing one technique for getting hold of shared > memory with another; it does nothing to the storage manager. > Eivind. -- Kent S. Gordon Architect iNetSpace Co. voice: (972)851-3494 fax:(972)702-0384 e-mail:kgor@inetspace.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message