Re: Compression and on-disk sorting

"Jim C. Nasby" <jnasby(at)pervasive(dot)com> writes:

> On Wed, May 17, 2006 at 12:55:53PM -0400, Greg Stark wrote:
> >
> > "Jim C. Nasby" <jnasby(at)pervasive(dot)com> writes:
> >
> > > Only if those spindles weren't all in a single RAID array and if we went
> > > through the trouble of creating all the machinery so you could tell
> > > PostgreSQL where all those spindles were mounted in the filesystem.
> >
> > I think the way you do this is simply by documenting that the admin should
> > create precisely one temp area per physical spindle (or raid array).
>
> And you still need some way to tell PostgreSQL about all of that.

No, my point was that you tell Postges how many spindles you have and where to
find them by creating precisely one temp area on each spindle. It then knows
that it should strive to maximize sequential reads within one temp area and
expect switching between temp areas (which represent multiple spindles) to be
better than multiplexing multiple tapes within a single temp area (which
represents a single spindle).

--
greg