Re: Parallel query execution

On Wed, Jan 16, 2013 at 01:37:28PM +0900, Michael Paquier wrote:
> 
> 
> On Wed, Jan 16, 2013 at 1:32 PM, Bruce Momjian <bruce@momjian.us> wrote:
> 
>     On Wed, Jan 16, 2013 at 01:28:18PM +0900, Michael Paquier wrote:
>     >
>     >
>     > On Wed, Jan 16, 2013 at 1:22 PM, Josh Berkus <josh@agliodbs.com> wrote:
>     >
>     >     Claudio, Stephen,
>     >
>     >     It really seems like the areas where we could get the most "bang for
>     the
>     >     buck" in parallelism would be:
>     >
>     >     1. Parallel sort
>     >     2. Parallel aggregation (for commutative aggregates)
>     >     3. Parallel nested loop join (especially for expression joins, like
>     GIS)
>     >
>     > parallel data load? :/
> 
>     We have that in pg_restore, and I think we are getting parallel dump in
>     9.3, right?  Unfortunately, I don't see it in the last 9.3 commit-fest.
>     Is it still being worked on?
> 
> Not exactly, I meant something like being able to use parallel processing when
> doing INSERT or COPY directly in core. If there is a parallel processing
> infrastructure, it could also be used for such write operations. I agree that
> the cases mentioned by Josh are far more appealing though...

I am not sure how a COPY could be easily parallelized, but I supposed it
could be done as part of the 1GB segment feature.  People have
complained that COPY is CPU-bound, so it might be very interesting to
see if we could offload some of that parsing overhead to a child.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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