Re: Tsearch2 performance on big database

On Tue, 22 Mar 2005 15:36:11 +0300 (MSK), Oleg Bartunov <oleg@sai.msu.su> wrote:
> On Tue, 22 Mar 2005, Rick Jansen wrote:
>
> > Hi,
> >
> > I'm looking for a *fast* solution to search thru ~ 4 million records of book
> > descriptions. I've installed PostgreSQL 8.0.1 on a dual opteron server with
> > 8G of memory, running Linux 2.6. I haven't done a lot of tuning on PostgreSQL
> > itself, but here's the settings I have changed so far:
> >
> > shared_buffers = 2000 (anything much bigger says the kernel doesnt allow  it,
> > still have to look into that)
>
> use something like
> echo "150000000" > /proc/sys/kernel/shmmax
> to increase shared memory. In your case you could dedicate much more
> memory.
>
>         Regards,
>                 Oleg

And Oleg should know.  Unless I'm mistaken, he (co)wrote tsearch2.
Other than shared buffers, I can't imagine what could be causing that
kind of slowness.  EXPLAIN ANALYZE, please?

As an example of what I think you *should* be seeing, I have a similar
box (4 procs, but that doesn't matter for one query) and I can search
a column with tens of millions of rows in around a second.

--
Mike Rylander
mrylander@gmail.com
GPLS -- PINES Development
Database Developer
http://open-ils.org