FreeBSD and MySQL - mysqld eats CPU alive

[Kevin D. Kinsey, DaleCo, S.P.]

<removed hackers@, database@>

Before the rest of the message ... I think it'd be best not to "shotgun"
your mails like this...

adp wrote:

>I recently posted the following message to MySQL discussion list. The
>response there, and the one I keep finding on Google, is that this is a
>long-standing issue betweeen FreeBSD and MySQL. For me this has been
>happening since FreeBSD 4.4.
>
>I have one site where we are going to have to move to Linux. I would much
>prefer keeping us on FreeBSD, but we just can't afford the downtime anymore.
>Another site is looking at moving to PostgreSQL on FreeBSD.
>
>Any help on this? Googling shows a long history of people having these
>problems but no solutions. Please don't give me a URL to a Google showing
>others having this problem--I've seen that and more. I want to know if there
>is a solution. Any help is appreciated!
>
>...
>
>I have several MySQL and FreeBSD installs across a few different sites, and
>I consistently have problems with mysqld. It will begin to eat up all of the
>CPU and eventually become unresponsive (or the machine will just burn). I
>can't seem to manually reproduce this, but given enough time a FreeBSD box
>with mysqld will go down.
>
>Our servers are generally heavily loaded.
>
>I would say that I'm doing something wrong (although what I could be doing
>wrong I'm not sure), but I recently began working with another company that
>has the EXACT SAME PROBLEM. They are even thinking of moving to PostgreSQL,
>but we are trying to fix mysqld instead for now.
>
>This behavior has been seen on:
>
>FreeBSD 4.4, 4.7, 4.9, 4.10
>MySQL 3.x and 4.x
>Typical load: 50 qps
>With and without replication enabled.
>Some sites are SELECT heavy, some are INSERT heavy.
>
>For one site I think we will be moving from FreeBSD to Linux for the MySQL
>servers since MySQL seems to run like a champ on Linux. We will continue to
>use FreeBSD for everything else.
>
>Anyone experienced this problem? Is it mysqld or FreeBSD? I can't pinpoint
>the exact issue.
>  
>

It's certain combinations of the two, best I can tell.  Looks like you
can stay with FBSD if you want to do the tweaking --- be sure and
read the second article if your are going to read the first ....

"FreeBSD or Linux for your MySQL Server?"
    http://jeremy.zawodny.com/blog/archives/000203.html

"Revisiting FreeBSD vs. Linux for MySQL"
    http://jeremy.zawodny.com/blog/archives/000697.html

HTH,

Kevin Kinsey
DaleCo, S.P.