Re: Parallel query execution

On Wed, Jan 16, 2013 at 05:04:05PM -0800, Jeff Janes wrote:
> On Tuesday, January 15, 2013, Stephen Frost wrote:
>
> * Gavin Flower (GavinFlower(at)archidevsys(dot)co(dot)nz) wrote:
> > How about being aware of multiple spindles - so if the requested
> > data covers multiple spindles, then data could be extracted in
> > parallel. This may, or may not, involve multiple I/O channels?
>
> Yes, this should dovetail with partitioning and tablespaces to pick up
> on exactly that.
>
>
> I'd rather not have the benefits of parallelism be tied to partitioning if we
> can help it. Hopefully implementing parallelism in core would result in
> something more transparent than that.

We will need a way to know we are not saturating the I/O channel with
random I/O that could have been sequential if it was single-threaded.
Tablespaces give us that info; not sure what else does.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +