Tuning Postgresql on FreeBSD 5.1
paul at pathiakis.com
Tue Aug 26 11:39:18 PDT 2003
I've tried disabling HTT in the BIOS (it's an Intel board). I've disable
HTT, saved the changes and the kernel is still seeing 4 CPUs when it boots.
On Tuesday 26 August 2003 12:44 am, Marc G. Fournier wrote:
> > > Again, the machine is a twin 2.8 Xeon HTT machine. HTT is turned on
> > > and the machine sees 4 cpus.
> > Have you played with toggling the sysctl machdep.cpu_idle_hlt?
> In fact, disabled HTT altogether ... I have a machine with pretty much the
> same specs (2.4 vs 2.8 Xeon's) and I found performance noticeably improved
> with HTT disabled ... not just with processes, but with interactive
> sessions as well ...
> > >From your postgresql.conf:
> > >
> > > shared_buffers = 48000 # min max_connections*2 or 16, 8KB each
> > WHOA! This is too high by a factor of about 10. You probably want a
> > shared buffers set to 4096.
> Why? If you have the memory and all that ... All my production servers
> /usr/local/bin/postmaster -B 40960 -N 512 -i -p 5432
> -D/usr/local/pgsql/5432 -S (postgres)
> > > sort_mem = 32768 # min 64, size in KB
> > This also seems high, divide by 8 and you're at a more reasonable
> > level.
> Again, depends on alot of things here ... if he only has the one
> connection to the DB, allowing for 32M of RAM to be used for sorting isn't
> a bad thing, since it keeps the sorts off of the hard drive ... that is
> one stat that I wish we kept somehow ... "max sort size" ...
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