Re: Moving pgstat.stat and pgstat.tmp

On Monday 03 December 2007 20:22, Erik Jones wrote:
> On Dec 3, 2007, at 6:10 PM, Tom Lane wrote:
> > Erik Jones <erik(at)myemma(dot)com> writes:
> >> 8.2.5 on Solaris 10. Before we upgraded to 8.2.4 it was doing about
> >> 65 Mbs/sec. Interestingly, a while back we were running with the
> >> data directory mounted with forcedirectio and saw none of this, I'm
> >> guessing that fsync calls would have something to do with that?
> >
> > Hmm ... no, because the stats file never gets fsync'd. I should think
> > that forcedirectio would have made things worse.
>
> Interesting. If this is anything you'd like to look into I can
> provide whatever diagnostic output you need (iostat, vmstat, dtrace
> script outputs, etc...) but I do have to reiterate that we are an
> extreme corner case due to out schema size. For now, is renaming the
> #define'd paths for the stats file and temp file sufficient for
> moving them? Basically, we'd like to move them onto a RAM disk to
> give our disks a break.
>

Yeah, we've noticed the same problem (pgstat is the most active file on the
system... uncovered in much the same way... go solaris). Actually I was
wondering if it could be done with symlinks, a la moving xlogs. Since we do
custom builds, that's not a real issue, but I was curious.

--
Robert Treat
Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL