Re: Possible Threading problem with -CURRENT / MySQL?

welcome to our hell. we've been experiencing mysql problems on freebsd 5.x
as well. it sounds like scheduler/threading is to blame but we were not
able to give sufficient or proper motivation to the folks who could
examine this deeper - we even offered $500 cash to whomever stepped up to
help resolve this.

linux runs almost 2x as fast on the same hardware with no configuring -
and we get nearly the same results running in single CPU mode vs. dual CPU
mode on fbsd... something is definately fubar with the mysql+fbsd5.x
combination.



On Mon, 14 Jun 2004, Lasse Laursen wrote:

> Hi,
>
> I posted this on the 2freebsq-questions" list some time ago but didn't get
> any response. Maybe someone on this list can help:
>
> We are running MySQL 4.0.20 on FreeBSD 5.2-CURRENT. The machine is a dual
> Xeon with 4GByte of memory with HTT enabled.
>
> Some info about the system:
>
> FreeBSD dbnode3 5.2-CURRENT FreeBSD 5.2-CURRENT #0: Tue Jun  8 14:41:02 CEST
> 2004     laursen_at_dbnode3:/usr/obj/usr/src/sys/DBNODE3  i386
>
> the /etc/libmap.conf contains:
>
> libc_r.so.5     libpthread.so.1
> libc_r.so       libpthread.so
>
> /etc/make.conf contains:
>
> # -- use.perl generated deltas -- #
> # Created: Wed Jun  9 10:18:52 2004
> # Setting to use base perl from ports:
> PERL_VER=5.8.4
> PERL_VERSION=5.8.4
> PERL_ARCH=mach
> NOPERL=yo
> NO_PERL=yo
> NO_PERL_WRAPPER=yo
>
> MySQL 4.0.20 was compiled with --without-libwrap (libwrapper seems to be
> broken) and WITH_PROC_SCOPE_PTH set to yes.
>
> WE use the SCHED_ULE, and:
>
> # Memory options
> options         MAXDSIZ="(1536*1024*1024)"
> options         MAXSSIZ="(1024*1024*1024)"
> options         DFLDSIZ="(1536*1024*1024)"
>
> The server runs fine until a single thread/query suddenly locks up the
> entire MySQL daemon. After that all queries are just queued and a restart of
> the daemon is needed to unlock the system. The system itself is stable
> enough as far as I can see. 'top' reports a lot of locks (*Giant) so I
> assume that it's some weird problem with the threading? We used to use
> FreeBSD on non-SMP machines without any problems.
>
> I have tried with linux threads as well but the same problem occurs.
>
> Have anyone experienced any similar problems and found a solution to this
> rather weird problem?
>
> Feel free to request any further information about the system/setup and I
> will do my best to provide it to the list.
>
> Regards
> --
> Lasse Laursen · VP, Hosting Technology · NetGroup Processing Aps
> St. Kongensgade 40H · DK-1264 Copenhagen K, Denmark
> Phone: +45 3370 1526 · Fax: +45 3313 0066
>
> - Don't be fooled by cheap finnish imitations - BSD is the One True Code
>
>
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