From owner-freebsd-stable Wed Dec 12 20:19:49 2001 Delivered-To: freebsd-stable@freebsd.org Received: from mail.viasoft.com.cn (unknown [61.153.1.177]) by hub.freebsd.org (Postfix) with ESMTP id 0159537B41B for ; Wed, 12 Dec 2001 20:19:42 -0800 (PST) Received: from viasoft.com.cn (davidwnt.viasoft.com.cn [192.168.1.239]) by mail.viasoft.com.cn (8.9.3/8.9.3) with ESMTP id MAA03945; Thu, 13 Dec 2001 12:27:07 +0800 Message-ID: <3C182B0E.7030809@viasoft.com.cn> Date: Thu, 13 Dec 2001 12:14:06 +0800 From: David Xu User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:0.9.4) Gecko/20011019 Netscape6/6.2 X-Accept-Language: en-us MIME-Version: 1.0 To: Tom Cc: Andrew Tulloch , freebsd-stable@FreeBSD.ORG Subject: Re: SMP and MySQL/threads References: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Tom wrote: >On Thu, 13 Dec 2001, David Xu wrote: > >>If you need performance, keep it with Linux until FreeBSD 5.0 is ready. >>current pthread implement in FreeBSD 4 is user level thread, and all >>disk access will >>be serialized and whole threads can only run in one processor. >> > > Disk access will be serialized? pthreads is all userland, which is >true, but all userland programs can issue non-blocking IO requests. >pthreads does (must) use nonblocking IO. > truely? you can not make disk I/O nonblocking. there is no effect to make disk file handle nonblocking, you are always blocked when doing disk I/O. > > No one seems to have mentioned any MySQL thread issues. For instance, >most MySQL table types serialize all INSERT and UPDATEs. Only one thread >can be writing at a time. A new table type fixes this problem, but >currently lacks online backup! > >Tom > disk access will be serialized even if mysql server is accessing different tables(yet different files). -- David Xu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message