From: | Alex Hayward <xelah-pgsql(at)xelah(dot)com> |
---|---|
To: | "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com> |
Cc: | Mark Kirkwood <markir(at)paradise(dot)net(dot)nz>, Vivek Khera <vivek(at)khera(dot)org>, Postgresql Performance <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Best OS & Configuration for Dual Xeon w/4GB & Adaptec |
Date: | 2006-03-21 12:22:31 |
Message-ID: | Pine.LNX.4.58.0603211217420.27598@sphinx.mythic-beasts.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-performance |
On Tue, 21 Mar 2006, Jim C. Nasby wrote:
> On Tue, Mar 21, 2006 at 11:03:26PM +1200, Mark Kirkwood wrote:
> >
> > So its really all about accounting, in a sense - whether pages end up in
> > the 'Buf' or 'Inactive' queue, they are still cached!
>
> So what's the difference between Buf and Active then? Just that active
> means it's a code page, or that it's been directly mapped into a
> processes memory (perhaps via mmap)?
I don't think that Buf and Active are mutually exclusive. Try adding up
Active, Inactive, Cache, Wired, Buf and Free - it'll come to more than
your physical memory.
Active gives an amount of physical memory. Buf gives an amount of
kernel-space virtual memory which provide the kernel with a window on to
pages in the other categories. In fact, I don't think that 'Buf' really
belongs in the list as it doesn't represent a 'type' of page at all.
--
Alex Hayward
Seatbooker
From | Date | Subject | |
---|---|---|---|
Next Message | Steinar H. Gunderson | 2006-03-21 12:29:54 | Re: Migration study, step 1: bulk write performance |
Previous Message | Jim C. Nasby | 2006-03-21 12:22:11 | WAL logging of SELECT ... INTO command |