Re: Out of free buffers... HELP!

Ok, can someone explain to me why this first query might run faster than the
second?

select src,dst,count(dst) from data;

select src,dst,count(*) from data;

I've always used the second form. If the first is faster, I need to know.

Thanx,
Mike Diehl,
Network Monitoring Tool Devl.
Sandia National Laboratories.
(505) 284-3137
jdiehl(at)sandia(dot)gov

> -----Original Message-----
> From: Haller Christoph [mailto:ch(at)rodos(dot)fzk(dot)de]
> Sent: September 18, 2001 7:18 AM
> To: jdiehl(at)sandia(dot)gov
> Cc: pgsql-sql(at)postgresql(dot)org
> Subject: Re: [SQL] Out of free buffers... HELP!
>
>
> As long as there are no nulls allowed in column 'dst' the
> select src,dst,count(dst) from ...
> should retrieve the same result.
> Try it. It should run faster anyway.
> Maybe there are other ways to word your query, but without
> more knowledge about your table structure and intentions
> I can't tell you what.
> Alternatively, you may want to report your error to the
> [HACKERS] mailing list - there you might even find more
> detailed support.
> Regards, Christoph
> >
> > Hi all.
> >
> > I sent this once before, but didn't see it appear on the
> list... So here we
> > go again...
> >
> > I have a large query that I'm trying to run, but it never
> finishes. I
> > get an error message and it quits.
> >
> > I'm doing:
> >
> > psql ids -c 'select src,dst,count(*) from brick* where src_port=135
> > group by src,dst' > /tmp/135.dat
> >
> > and I get:
> >
> > ERROR: out of free buffers: time to abort !
> >
> > Any ideas on how to get this query to run?
> >
> > Thanx,
> > Mike Diehl.
> >
> >
> > ---------------------------(end of
> broadcast)---------------------------
> > TIP 1: subscribe and unsubscribe commands go to
> majordomo(at)postgresql(dot)org
> >
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
> (send "unregister YourEmailAddressHere" to
> majordomo(at)postgresql(dot)org)
>