Re: High I/O writes activity on disks causing images on browser to lag and not load

In response to Jennifer Trey <jennifer(dot)trey(at)gmail(dot)com>:

> Hmm.. I doesn't look it made it to the mailing list. I guess you can't
> attach a file then.----
> Finally!
> I did use the programs suggested by Michael, but I actually found it a
> little before you wrote :P
>
> Filtering out with the pid showed that it was the file
> pgdata/global/pgstat.tmp

That's the statistics collector -- which makes sense, depending
on your settings, it has to write stats for every operation done in the
database.

I believe you can disable stats collection entirely, although it will
force you to abandon autovacuum and start vacuuming manually:
http://www.postgresql.org/docs/8.3/static/runtime-config-statistics.html

Additionally, this convinces me further that you're chasing the wrong
problem. The stats collector writes tiny bits of information to disk
every time you execute a command. If your system is slow because of this
tiny bit of I/O, then something else is wrong. Either your system is
already near its max capacity and this is pushing it over the edge, or
you're fixing the wrong problem.

In any event, go ahead and turn off stats collection and see if
performance improves, but I'll be utterly shocked if it makes any
significant difference.

My advice to you is to take a step back and define the problem in more
general terms. You have a performance problem, drop any preconceptions
about what's causing it and start by isolating the problem itself. Sorry
if this sounds offensive, but this thread has shown a pattern with you
of chasing things without doing proper research first, and making
assumptions about what's causing the problem, without even knowing what
the problem is.

--
Bill Moran
http://www.potentialtech.com
http://people.collaborativefusion.com/~wmoran/