From: | Aditya <aditya(at)grot(dot)org> |
---|---|
To: | sfpug(at)postgresql(dot)org |
Subject: | Re: Freebsd vs linux and hardware question |
Date: | 2003-09-19 23:39:50 |
Message-ID: | 20030919233950.GA69921@mighty.grot.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | sfpug |
On Fri, Sep 19, 2003 at 03:48:35PM -0700, Dror Matalon wrote:
> > But hey, why are you asking this stuff? Don't you run Zapatec's stuff off a
> > huge SAN?
>
> It's not so Huge, out netapp is less than 200 Megs. But the real issue
> is that it works really well for small data sets but not for big ones.
BTW, he means 200 Gigs...
> We're working on a new application that will handle millions of rows.
> Currently the table size is half a gig and growing.
>
> On this type of application the netapp is slower than local disks. So
> we're thinking of setting up a new machine with plenty of power. I'm
> trying to figure out what the right configuration would be both in terms
> of the hardware and the OS.
the main problem is that the data is a time-series and now() isn't immutable
under Postgres 7.2 meaning that indices on a timestamp field don't work...ie.
select * from weblogs where ts > (now() - interval '7 days');
will always use a sequential scan since now() isn't cacheable. Worse yet,
there is no "immutable" flag for functions under 7.2 so we can't wrap now() in
a function marked immutable...(thanks to Stephan Szabo who explained this to
me a few months ago on sfpug)
a new database machine would allow us to use a newer version of Postgres which
could use an index and would avoid having to transfer an entire table from the
NAS for a sequential scan...(the network interface is a bottle-neck in that
case)
Aditya
From | Date | Subject | |
---|---|---|---|
Next Message | Josh Berkus | 2003-09-20 00:37:22 | Re: Freebsd vs linux and hardware question |
Previous Message | Dror Matalon | 2003-09-19 23:28:42 | Re: Freebsd vs linux and hardware question |