Re: Version 7 question - Mailing list pgsql-performance

8192 is only 64 megs of RAM, not much, but a good number.  Keep in mind
that the kernel tends to be better at buffering huge amounts of disk,
while postgresql is better left to use buffers that are large enough for
the current working set (i.e. not your whole database, just the largest
amount of data you're slinging about on a regular basis in one query.)

On a machine with 1.5 gig of RAM, I've found settings as high as 32768
(256 megs of ram) to run well, but anything over that doesn't help.  Of
course, we don't toss around more than a hundred meg or so at a time.   If
our result sets were in the gigabyte range, I'd A: want more memory and B:
Give more of it to postgresql.

The original poster was, I believe running 7.0.x, which is way old, so no,
I don't think there was an equivalent of effective_cache_size in that
version.  Upgrading would be far easier than performance tuning 7.0. since
the query planner was much simpler (i.e. more prone to make bad decisions)
in 7.0.

On Tue, 1 Jul 2003, Michael Mattox wrote:

> I have my shared buffers at 8192 and my effective cache at 64000 (which is
> 500 megs).  Depends a lot on how much RAM you have.  I have 1.5 gigs and
> I've been asking my boss for another 512megs for over a month now.  I have
> no idea if my buffers are too high/low.
>
> Michael
>
> > -----Original Message-----
> > From: pgsql-performance-owner@postgresql.org
> > [mailto:pgsql-performance-owner@postgresql.org]On Behalf Of Hilary
> > Forbes
> > Sent: Tuesday, July 01, 2003 2:10 PM
> > To: pgsql-performance@postgresql.org
> > Subject: [PERFORM] Version 7 question
> >
> >
> > I'm just trying to improve performance on version 7 before doing
> > some tests and hopefully upgrading to 7.3.
> >
> > At the moment we have
> > B=64  (no  of shared buffers)
> > N=32 (no of connections)
> > in postmaster.opt which I take it is the equivalent of the new
> > postgresql.conf file.
> >
> >  From all that is being written about later versions I suspect
> > that this is far too low.  Would I be fairly safe in making the
> > no of shared buffers larger?  Also is there an equivalent of
> > effective_cache_size that I can set for version 7?
> >
> > Many thanks in advance
> > Hilary
> >
> >
> >
> >
> > Hilary Forbes
> > -------------
> > DMR Computer Limited:   http://www.dmr.co.uk/
> > Direct line:  01689 889950
> > Switchboard:  (44) 1689 860000  Fax: (44) 1689 860330
> > E-mail:  hforbes@dmr.co.uk
> >
> > **********************************************************
> >
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 5: Have you checked our extensive FAQ?
> >
> >                http://www.postgresql.org/docs/faqs/FAQ.html
> >
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: Have you checked our extensive FAQ?
>
>                http://www.postgresql.org/docs/faqs/FAQ.html
>