Re: High load,

On Thu, Jan 27, 2011 at 5:31 AM, Michael Kohl <michael(dot)kohl(at)tupalo(dot)com> wrote:
> we are running a fairly big Ruby on Rails application on Postgres 8.4.
> Our traffic grew quite a bit lately, and since then we are facing DB
> performance issues. System load occasionally explodes (around 170
> yesterday on a 16 core system), which seems to be caused by disk I/O
> (iowait in our Munin graphs goes up significantly during these
> periods). At other times the laod stays rather low under pretty much
> the same circumstances.
[...]
> [1] http://www.linux.com/learn/tutorials/394523-configuring-postgresql-for-pretty-good-performance
> [2] http://www.pgcon.org/2010/schedule/events/210.en.html

At the risk of shameless self-promotion, you might also find this helpful:

http://rhaas.blogspot.com/2010/12/troubleshooting-database.html

It's fairly basic but it might at least get you pointed in the right
direction...

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company