libpthread / mysql41-server

[Daniel Eischen]

On Sun, 21 Mar 2004, Andy Hilker wrote:

> Hi,
> 
> You (Craig Rodrigues) wrote:
> > On Sat, Mar 20, 2004 at 12:35:56PM +0100, Andy Hilker wrote:
> > > Hi,
> > > 
> > > i have used mysql41 with linuxthreads since a few month without problems.
> > > Now linuxthreads from ports does not compile and i wanted to try
> > > without linuxthreads.
> > 
> > Look at the mailing list archives for the freebsd-threads
> > mailing list.  There was some discussion about mysql.
> > 
> > http://lists.freebsd.org/pipermail/freebsd-threads
> > http://lists.freebsd.org/pipermail/freebsd-threads/2004-January/
> 
> It seems that i have a similar issue like
> 
> http://lists.freebsd.org/pipermail/freebsd-threads/2004-February/001660.html
> 
> But maybe it is not fixed or exists again.
> Bumping up thread sysctls or using libmap.conf are not better. mySQL
> becomes very unresponsive.

Mysql uses scope system threads which are limited to
kern.threads.max_groups_per_proc.  System scope threads
seem to have unfair scheduling also.  I use SCHED_4BSD
and this patch to mysql40-server to make it use process
scope threads and it works much better:

  http://people.freebsd.org/~deischen/mysql40-server.diffs

I haven't made a patch to other versions of mysql, but I
have sent the maintainer the patch.

-- 
Dan Eischen