Re: mysql (smp) performance

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From
Tom Samplonius <tom@sdf.com>
Date
10 Jan 2001 20:56:16
Subject
Re: mysql (smp) performance
Message-ID
Pine.BSF.4.05.10101102005510.21469-100000@misery.sdf.com

In reply to

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On Wed, 10 Jan 2001, David Miller wrote:

> On Wed, 10 Jan 2001, Tom Samplonius wrote:
>
> > On Wed, 10 Jan 2001, Lauri Laupmaa wrote:
> >
> > ...
> > > It seems that on SMP mysql doesn't scale well. (currently testing on
> > > dual 833 PIII and running on couple older dual systems)
> >
> > Because there is no such thing as SMP mysql. It is a single process,
> > and can only run on a single processor at a time.
>
> My understanding is that it's single process but multithreaded. When I
> asked a very similar question on a mysql list a year ago I was told that
> on linux it ran much better on multiple cpu's.

You can however compile mysql with linuxthreads. BTW, the linuxthreads
is a full FreeBSD port of the linuxthreads package, which provides
pseudo-process threads. These threads are scheduled as processes and you
will see a performance improvement with SMP. Linux threads are rather
heavy weight, so this solution has not been included as the standard
thread package.

Standard FreeBSD theads are now (as 4.2-stable) solid and reliable.
Reliability has been inconsistant. I have a 3.5-STABLE system using mysql
and the native threads on a 2 GB database. No problems. Standard FreeBSD
threads have less overhead that threads on Linux, or Linux-like threads on
FreeBSD.

> --- David

Tom



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