Re: Parallel Seq Scan

On 08-04-2015 PM 12:46, Amit Kapila wrote:
> Going forward, I think we can improve the same if we decide not to shutdown
> parallel workers till postmaster shutdown once they are started and
> then just allocate them during executor-start phase.
> 

I wonder if it makes sense to invent the notion of a global pool of workers
with configurable number of workers that are created at postmaster start and
destroyed at shutdown and requested for use when a query uses parallelizable
nodes. That way, parallel costing model might be better able to factor in the
available-resources-for-parallelization aspect, too. Though, I'm not quite
sure how that helps solve (if at all) the problem of occasional unjustifiable
resource consumption due to parallelization.

Thanks,
Amit