> "DM" == Dror Matalon <[EMAIL PROTECTED]> writes:
DM> which brings me back to my question why not make Freebsd use more of its
DM> memory for disk caching and then tell postgres about it.
Because this is a painfully hard thing to do ;-(
It involves hacking a system header file and recompil
On Thu, Feb 26, 2004 at 06:06:06PM -0500, Christopher Weimann wrote:
> On 02/26/2004-11:16AM, Dror Matalon wrote:
> > >
> > > effective_cache_size changes no cache settings for postgresql, it simply
> > > acts as a hint to the planner on about how much of the dataset your OS /
> > > Kernel / Dis
> "CW" == Christopher Weimann <[EMAIL PROTECTED]> writes:
>> which brings me back to my question why not make Freebsd use more of its
>> memory for disk caching and then tell postgres about it.
>>
CW> Because you can't. It already uses ALL RAM that isn't in use for
CW> something else.
No,
I noticed this passage too, but ...
Quoting from http://www.daemonnews.org/21/freebsd_vm.html :
*
When To Free a Page*
Since the VM system uses all available memory for disk caching, there
^
The VM system, as you can see from the article, is focused on paging and
On Mon, Mar 01, 2004 at 08:30:58PM +1300, Mark Kirkwood wrote:
>
>
> Shridhar Daithankar wrote:
>
> >Dror Matalon wrote:
> >
> >>I've read Matt Dillon's discussion about the freebsd VM at
> >>http://www.daemonnews.org/21/freebsd_vm.html and I didn't see him
> >>saying that Freebsd uses all t
Shridhar Daithankar wrote:
Dror Matalon wrote:
I've read Matt Dillon's discussion about the freebsd VM at
http://www.daemonnews.org/21/freebsd_vm.html and I didn't see him
saying that Freebsd uses all the free RAM for disk cache. Would you care
to provide a URL pointing to that?
Quoting
On 02/26/2004-11:16AM, Dror Matalon wrote:
> >
> > effective_cache_size changes no cache settings for postgresql, it simply
> > acts as a hint to the planner on about how much of the dataset your OS /
> > Kernel / Disk cache can hold.
>
> I understand that. The question is why have the OS, in t
On 02/26/2004-01:58PM, Dror Matalon wrote:
>
> Sigh.
>
Sigh, right back at you.
> which brings me back to my question why not make Freebsd use more of its
> memory for disk caching and then tell postgres about it.
>
Because you can't. It already uses ALL RAM that isn't in use for
something
On Friday 27 February 2004 21:03, scott.marlowe wrote:
> Linux doesn't work with a pre-assigned size for kernel cache.
> It just grabs whatever's free, minus a few megs for easily launching new
> programs or allocating more memory for programs, and uses that for the
> cache. then, when a request c
I guess the thing to do is to move this topic over to a freebsd list
where we can get more definitive answers on how disk caching is handled.
I asked here since I know that FreeBsd is often recommended,
http://www.varlena.com/varlena/GeneralBits/Tidbits/perf.html#
as a good platform for postgres, a
On Fri, 27 Feb 2004, Shridhar Daithankar wrote:
> Dror Matalon wrote:
>
> > Let me try and say it again. I know that setting effective_cache_size
> > doesn't affect the OS' cache. I know it just gives Postgres the *idea*
> > of how much cache the OS is using. I know that. I also know that a
> > c
Dror Matalon wrote:
Let me try and say it again. I know that setting effective_cache_size
doesn't affect the OS' cache. I know it just gives Postgres the *idea*
of how much cache the OS is using. I know that. I also know that a
correct hint helps performance.
I've read Matt Dillon's discussion abo
Hi,
We have postgres running on freebsd 4.9 with 2 Gigs of memory. As per
repeated advice on the mailing lists we configured effective_cache_size
= 25520 which you get by doing `sysctl -n vfs.hibufspace` / 8192
Which results in using 200Megs for disk caching.
Is there a reason not to increase t
On Fri, Feb 27, 2004 at 05:47:47AM +0800, Christopher Kings-Lynne wrote:
> > We have postgres running on freebsd 4.9 with 2 Gigs of memory. As per
> > repeated advice on the mailing lists we configured effective_cache_size
> > = 25520 which you get by doing `sysctl -n vfs.hibufspace` / 8192
> >
> >
> We have postgres running on freebsd 4.9 with 2 Gigs of memory. As per
> repeated advice on the mailing lists we configured effective_cache_size
> = 25520 which you get by doing `sysctl -n vfs.hibufspace` / 8192
>
> Which results in using 200Megs for disk caching.
effective_cache_size does nothin
On Thu, 26 Feb 2004, Dror Matalon wrote:
> On Thu, Feb 26, 2004 at 11:55:31AM -0700, scott.marlowe wrote:
> > On Thu, 26 Feb 2004, Dror Matalon wrote:
> >
> > > Hi,
> > >
> > > We have postgres running on freebsd 4.9 with 2 Gigs of memory. As per
> > > repeated advice on the mailing lists we con
Thanks for the pointer. So
maxbufspace = nbuf * BKVASIZE;
Which is confirmed in
http://unix.derkeiler.com/Mailing-Lists/FreeBSD/performance/2003-09/0045.html
and it looks like there's a patch by Sean Chittenden at
http://people.freebsd.org/~seanc/patches/patch-HEAD-kern.nbuf
that does what I
On Thu, Feb 26, 2004 at 11:55:31AM -0700, scott.marlowe wrote:
> On Thu, 26 Feb 2004, Dror Matalon wrote:
>
> > Hi,
> >
> > We have postgres running on freebsd 4.9 with 2 Gigs of memory. As per
> > repeated advice on the mailing lists we configured effective_cache_size
> > = 25520 which you get b
On 26 Feb 2004 at 13:58, Dror Matalon wrote:
>
> which brings me back to my question why not make Freebsd use more of its
> memory for disk caching and then tell postgres about it.
>
I think there is some confusion about maxbufsize and hibufspace. I looking at a
comment in the FreeBSB s
On Thu, 26 Feb 2004, Dror Matalon wrote:
> Hi,
>
> We have postgres running on freebsd 4.9 with 2 Gigs of memory. As per
> repeated advice on the mailing lists we configured effective_cache_size
> = 25520 which you get by doing `sysctl -n vfs.hibufspace` / 8192
>
> Which results in using 200Megs
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