MySQL and libpthread

[Daniel Eischen]

On Tue, 20 Apr 2004, Mike Silbersack wrote:

> 
> I haven't had time to fully track it down yet, but FYI I've found that
> MySQL and libpthread don't seem to get along well for me; with sources
> from april 12th and mysql 4.1 from ports, mysqld just seems to hang for
> long periods of time, and is unkillable.  When I libmap it to libthr or
> libc_r, all is well.

There are a lot of posts regarding mysql in the threads
archives.  Two things -- mysql with libwrap support doesn't
work with default CFLAGS (-march), and mysql uses scope
system threads which chew up more kernel resources and
can hang when you hit kern.threads.* limits.

To make mysql40 use scope process threads:

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

> The test I was running was simply mysql's included benchmark suite, using
> local socket connections to mysql.  If one of the libpthread developers
> can not reproduce this behavior, I'll try more tests later in the week to
> see if I can pin it down more.

I've got mysql40-server running here with the above patches
and a test script that causes creation of 1800 mysql threads.

-- 
Dan Eischen