Re: FreeBSD upgrade causes performance degredation

> We run BSD upgrade on 4.1 ...boot from the CD and select upgrade
> during the install. I haven't done anything to tune the postgres
> config...what is recommended?

Tons, but turning off fsync is the biggest/easiest win you can get.
Check out the online docs regarding performance tuning, they're quite
good.

You'll also probably want to turn on soft-updates. Type 'mount' and
see if anything similar to:

/dev/da0s1f on /opt (ufs, NFS exported, local, soft-updates)

If not, then you'll want to turn on soft-updates via the command
'tunefs -n enable /fs/mount/point'. This is something you can read
about in the tuning(7) man page (EXCELLENT read that I recommend
everyone read through if you use FreeBSD).

> Eveything has been running fine out of the box up to this
> point. Further analysis indicates this could be a problem with the
> BSD upgrade, as performance seems to have improved after a clean
> install of FreeBSD 4.4.

That's odd... If you get a chance and are savvy with using cvsup,
check out the -STABLE branch because it has some new DIRPERF code that
gives at least a 3x speed up to doing a cvs update for a local copy of
FreeBSD and is probably going to have a significant increase in
performance for database operations as well (very disk IO intensive).
The DIRPERF code was MFC'ed 5 days after 4.4 was released. The other
tid-bit of code that may be useful is the DIRUHASH code (optional that
you'll have to compile into your kernel) which speeds up routines for
large number of files per directory. -sc