Re: pg 8.1.2 performance issue

On Saturday March 25 2006 9:55 pm, chris smith wrote:
> On 3/26/06, Ed L. <pgsql(at)bluepolka(dot)net> wrote:
> > On Saturday March 25 2006 9:36 pm, Ed L. wrote:
> > > I have a performance riddle, hoping someone can point me
> > > in a helpful direction. We have a pg 8.1.2 cluster using
> > > Apache::Sessions and experiencing simple UPDATEs taking
> > > sometimes 30+ seconds to do a very simply update, no
> > > foreign keys, no triggers:
> >
> > The table has 6800 rows over 18000 pages, and is getting a
> > minimum of many tens of thousands of updates per day with
> > queries like this:
>
> If you're updating that much, how often are you running
> 'analyze'? Are you running autovacuum? How often?

I count on the built-in autovacuum to do do analyzes (per 8.1.2
docs). I'm running autovacuum with the following non-default
parameters:

autovacuum = on
autovacuum_naptime = 600 # 10 minutes

With our set of 4 DBs, that amounts to once every 40 minutes for
the given database. I see "LOG: autovacuum: processing
database "xyz"" in the log, but I do not see any analyze/vacuum
commands being issued at all (does it log when it
analyzes/vacuums?).

Thanks,
Ed