Postgresql locks up server - no response at all

[Jon Noack]

On 08/04/04 15:34, Jeremy Chadwick wrote:
> I've seen this with our SuperMicro SuperServer 5013C-T, running mysqld.
> Please note that the server is "heavily loaded" (note the quotes); usually
> a load of around 0.50 to 1.00 at all times, with mysqld being the top
> process.  Server runs all latest -CURRENT builds.
> 
> Many people over in freebsd-threads mentioned this problem, and recommended
> all sorts-of different workarounds.  I tried every one available to me,
> except mucking with PREEMPTION (as I did not feel comfortable tinkering
> with a random .h file on the box; seemed to be a kernel-related thing,
> so I'd rather have just an "options" line for it -- I'm conditionally
> lazy).

The one you didn't try most likely was the culprit.  Robert Watson 
showed that PREEMPTION and threading don't play well together right now:
http://lists.freebsd.org/pipermail/freebsd-current/2004-July/031211.html

The thought is that PREEMPTION uncovers scheduler bugs, but nobody's 
figured it out at the moment.

> Wed Aug  4 13:28:35 PDT 2004
> * -CURRENT box is still alive and well.

PREEMPTION was turned off on August 1st, so if you've updated since then 
things should have stabilized a bit:
http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/i386/include/param.h#rev1.72

Jon