Re: anyone run 4.7 on amd dualMP's

[Jonathan Disher <jdisher@xxxxxxxxx>]

On Fri, 20 Dec 2002, Josef Grosch wrote:

> On Fri, Dec 20, 2002 at 05:47:55PM -0500, Jonathan Disher wrote:
> > On Fri, 20 Dec 2002, Eriq wrote:
> >
> > > just wondering how stable 4.7 would be on that hardware. has anyone tryed
> > > running dual MPs and what is there take on it or is intel better. I would
> > > like to go dual but not sure which way to go
> >
> > Yes, we have a dual MP2200 that is fast as hell.
> >
> > Our only current problem is that MySQL sucks on a FreeBSD machine with
> > more than 1 CPU.  I'm still eagerly awaiting 5.0-RELEASE to see if our
> > problems are fixed.
>
> I'm running FreeBSD 4.7-STABLE on dual P-II 350's and it is also pretty
> damn fast.
>
> Is your experence that your MySQL database is slow during writes or
> updates? You do know that MySQL is single threaded on a write? It locks the
> table on a write, as in an insert, update, or delete. Have you considered
> Postgresql?

On FreeBSD, MySQL locks itself to one thread per CPU when it detects
multiple CPUs.  We have a data conversion test that takes about 48 minutes
to run on a single AthlonMP 2200 CPU.  It takes 2h 03m with two CPUs.

The threading problems are FreeBSD's, not MySQL's.  This is a known issue
on both sides, and it is (supposedly) fixed in 5.0.  I've not had a chance
to test it yet, though.  With all that's going on at work, I haven't had a
chance to drop one of the release candidates on our test box and fire up a
conversion.

The consideration of PostgreSQL vs MySQL (vs Innobase vs BerkelyDB vs
Oracle vs whateverelse) is not my choice to make, and it would be too much
of a rewrite of our systems to move to Postgres.  We're hoping FreeBSD-5
will make life easier.

-j


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