Mysql server not able to stay running on anything but Linux?

NMH drumslayer2 at
Wed Oct 12 21:31:17 PDT 2005

--- Greg 'groggy' Lehey <grog at> wrote:

> Note the From: address.
> On Wednesday, 12 October 2005 at 13:16:22 -0700, NMH
> wrote:
> >
> > I am stuck with a delema and I feel like a damn
> troll. But.. I have
> > a Mysql Database that I posted about earlier. It
> seems that it is
> > only able to not die by running on BSD 4.11 with
> Linux Threads. My
> > boss is convinced this means that Linux is better
> for MySQL and
> > wants that installed now.
> >
> > We even got a support contact from Mysql that so
> far has gotten us
> > nothing for almost a month while our production
> database server died
> > up to 3 times a day.  (and lots of we're looking
> into it's)
> One of the reasons why you haven't got much more
> than "we're looking
> into it"s is because we haven't been able to
> reproduce the problem;
> you acknowledge this in follow-up mail quoted below.
> As you know from various threads on the FreeBSD
> lists, including this
> one, the typical answer is "works fine for me". 
> That doesn't mean
> that we're not taking your problems seriously, but
> we do have a
> significant issue just reproducing the problem.  We
> have a number of
> choices:
> 1.  Try different hardware or a different version of
> FreeBSD.  It's
>     conceivable that there's something about your
> specific hardware,
>     or about the combination of i386 kernel on amd64
> in general, that
>     triggers the problem.

 Yes possible. However the same hardware was used for
the earlier version machine that worked fine. IE
Freebsd 5.1-RELEASE-P11 and Mysql 4.0.18 worked on the
same hardware.

> 2.  Do debugging on your production servers.  This
> isn't really a
>     choice at all: it would involve even more down
> time.

  Yea not really an option.
> 3.  Get you to run a more stable version of FreeBSD
> while we
>     investigate the problem.  This is the method we
> chose.  I haven't
>     heard from you since the weekend, so I hope I'm
> correct in
>     understanding that you currently don't have
> stability problems.
>     On our side, we have installed FreeBSD 5.4 on
> one of our internal
>     machines, and we're trying to reproduce the
> problem there.

 So far we have had only one crash that seemed to have
been SCSI related. So far it has not happend again.
 One problem with replication that was a coding issue.
> > We were running fine but a little slow on FreeBSD
> 5.1-P11 and MySQL
> > 4.0.18.(apperantly before a big Lib change) We had
> to move quicker
> > than we wanted to a new server running FreeBSD 5.4
> and MySQL 4.11
> > (becouse of a dual HD death) Under production load
> the new 5.4
> > server fell over regulary. It has only now become
> stable by wiping
> > it and running it on FreeBSD 4.11 with Linux
> Threads. (it regularly
> > has over 400+ threads)
> Kris obviously understood that by this statement you
> meant a kernel
> crash.  My understanding is that only the mysqld
> server is crashing.
> Is this still correct?

 Yes only Mysqld would crash. Sometimes brb and
autorestart with minimal damage. Other times it would
die a horrible death and damage tons of data on its
way out. 
> > I want to try FreeBSD 5.4 AMD64 (the machines are
> Opteron) or 6.0
> > but my boss feels that would be a waste given that
> MYSQL doesn't
> > support Mysql on AMD64 well enough.
> I think it would be a good idea to try this.  It's
> one of the things
> that we intend to do in-house as soon as we can
> reproduce the problem
> at all.

 Yes however as I pointed out.. Just Trying things on
a production database is not desirable without some
serious indicators that its worthwhile. Last you wrote
you said you doubted that would do anything I believe.
 Also support for amd64 based mysql is listed as
Limited. As you said reproducing the problem is the
 However as I suggested I would have thought that if
mysql were really into solving the problem, someone
would have requested a login on the box to look at our
queries to see how they are. Are they 60% reads 40%
writes, are they many divergent queries bundled
together.. etc. IE come and see our production
database in action to see what needs to be replicated.

 I haven't seen anything like this. Now I don't know
much but to me if I can't replicate something it's
becouse I don't know enough about it.

> > Can anyone help or offer assistance to help track
> this down? Perhaps
> > also any annecdotes or examples I can show my boss
> that other people
> > have as busy MYSQL databases on BSD 5.X. We paid
> 3K to Mysql for
> > help and so far they have been unable to offer any
> clues as to why
> > ours will not stay stable on anything but Linux
> threads.
> Have you had any kind of crash under 4.x?  I don't
> think that the
> issue is so much linuxthreads as 5.x.

 5.1.. Old lib style No crashes
 5.4 .. Crashes like mad
 5.4 with libmap.conf to other threads works better..
 4.11 with Linux threads.. No Crashes.

 So yea.. But thats the other issue that makes it
hard. Is it Mysql or is it Freebsd or the interaction
and memory sharing going on. I hope that someone here
who deals with these things might actually read these
emails. Its just very frustrating.

> > As I say I only manage the server, I don't program
> the databases. Is
> > there anything I should/could look for database
> wise that could
> > trigger such things?
> So far we've had the machine up in-house and have
> not reproduced the
> problem.  If you have a spare machine that we could
> run under more
> typical conditions on your premises, this might
> help.

 We have one machine still running 5.4. But what to do
with it? I would love to convert it to amd64 but we
need some machine to still 5.4 so we can have
something to test.
> On Wednesday, 12 October 2005 at 17:07:57 -0400,
> Kris Kennaway wrote:
> >
> > Unfortunately you'll need to provide details of
> how it "fell over"
> > (e.g. panic messages + backtraces).
 I didn't see this email. 
 We did supply all that to you (greg and Mysql) as far
as I know. If you could share what is needed that
would be appreciatted.

> As I mention above, I think this is only a server
> crash.  I mentioned
> this on the list a couple of weeks ago: all the
> backtraces I have seen
> have been a SIGSEGV out of mutex_unlock_common.

 Your opinion on this given what you have seen of our

> >> Can anyone help or offer assistance to help track
> this down?
> >> Perhaps also any annecdotes or examples I can
> show my boss that
> >> other people have as busy MYSQL databases on BSD
> 5.X. We paid 3K to
> >> Mysql for help and so far they have been unable
> to offer any clues
> >> as to why ours will not stay stable on anything
> but Linux
> >> threads. I feel really sad that so far no one has
> responded to my
> >> posts and it feels like a victory for linux.
> >
> > If I was your boss I'd be asking why mysql hasn't
> delivered on their
> > support contract.
> Indeed.  I think we have, though.  There's a certain
> class of bugs
> which are almost impossible to fix because they're
> so hard to chase
> down.  This is one of them.

 Lucky us. :(
  But does that also mean that anyone else running 5.4
and Mysql will likely run into this when they reach
our  level of activity? 

> On Wednesday, 12 October 2005 at 14:41:54 -0700, NMH
> wrote:
> > --- Kris Kennaway <kris at> wrote:
> >
> >> If I was your boss I'd be asking why mysql hasn't
> delivered on
> >> their support contract.
> >
> > Well I think support has many meanings. I decided
> to look at what he
> > paid for and it says:
> >  We get "access" to the mysql devlopers...
> >  We get "access" to certified binaries. (none of
> which
> > are FreeBSD)
> >
> > So, sad as it may seem, if your running on
> FreeBSD, $3000.00 buys
> > you someone to talk to. It doesn't mean they have
> to say anything
> > meaningful back or within any reasonable time. :(
> We try to handle all problems within a reasonable
> time.  The fact that
> you're running FreeBSD does mean that you don't get
> certified
> binaries, but that's the only drawback.  And the
> fact that the time
> for this problem has been unreasonable has nothing
> to do with the fact
> you're running FreeBSD: it's because it's a bugger
> to track down.

 Right. Which is why I am here. Hoping to widing the
audience and ask for help rather than having to switch
to Linux to get this solved. I didn't see you posting
anything to ask others so I thought I would. As I said
sometimes the gift and curse of FreeBSD is most of its
users not needing or relying on commercial support for
hardware and software things. So we can be overlooked
as a market. 
 Greg. if you wouldn't mind sharing the info with Kris
I would appreciate it. If there is anything else
needed just ask.

 Be well!

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