Date: Thu, 13 Dec 2001 12:14:06 +0800 From: David Xu <davidx@viasoft.com.cn> To: Tom <tom@uniserve.com> Cc: Andrew Tulloch <andrewt@great4.co.uk>, freebsd-stable@FreeBSD.ORG Subject: Re: SMP and MySQL/threads Message-ID: <3C182B0E.7030809@viasoft.com.cn> References: <Pine.BSF.4.10.10112121937540.60319-100000@athena.uniserve.ca>
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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
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