11 messages in com.mysql.lists.mysqlRe: mysql speed - raw i/o under linux...
FromSent OnAttachments
David Haring02 Dec 1999 03:12 
Ed Carp02 Dec 1999 03:24 
srf...@mistik.net02 Dec 1999 10:42 
Michael Widenius02 Dec 1999 12:03 
Robert Seward02 Dec 1999 15:12 
brdo...@oro.net02 Dec 1999 15:46 
Paul DuBois02 Dec 1999 16:40 
Sasha Pachev02 Dec 1999 16:44 
brdo...@oro.net03 Dec 1999 06:02 
Sasha Pachev03 Dec 1999 08:32 
Steve Ruby03 Dec 1999 15:19 
Subject:Re: mysql speed - raw i/o under linux, Hoard memory allocator, SMP
From:Robert Seward (rsew@bluestone-consulting.com)
Date:12/02/1999 03:12:54 PM
List:com.mysql.lists.mysql

The Hoard memory allocator looks like you can drop it into any codebase and use it. It is just a replacement to malloc. Try compiling MySQL with it and benchmark it. If MySql performs better than without Hoard you know the answer to your question. And please share your results with list! ;-)

Raw I/O I have mixed feelings about that. The gains will be minimal at best, and you will lose a bit of stability when you crash. But it may help with 2 GB limits on file systems.

Thanks, Rob

srf@mistik.net wrote:

On Thu, 2 Dec 1999, Ed Carp wrote:

As raw i/o support is available for Linux as kernel patch, I would like to know if mysql can be run on raw i/o device under Linux and, if so, how would this impact mysql performance. Did anybody try this?

I brought this up a while back. Seems it wouldn't run any faster. And I didn't know you needed a kernel patch to do I/O direct to a disk partition.

i think he meant raw i/o device, not using the system buffers (sendfile() and the like). i believe this feature is partially available in Linux 2.2.x - extended by the rawio patch, but it's planned as one of the main features in Linux 2.4.x.

you still need to use the facilities in mysql (for example) to get the desired performance. of course, mysql doesnt have these in place. but maybe in a future version (?) *hint* :)

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