Re: Parallel Foreign Scans - need advice

Hi,

Don't top quote on these list...

On 2019-05-15 13:31:59 -0400, Korry Douglas wrote:
> Thanks for the quick answer Andres.  You’re right - it was parallel_tuple_cost that was getting in my way; my query
returnsabout 6 million rows  so I guess that can add up.
 
> 
> If I change parallel_tuple_scan from 0.1 to 0.0001, I get a parallel foreign scan.
> 
> With 4 workers, that reduces my execution time by about half.  

Then you probably need to adjust the scan costs you have.


> But, nworkers_launched is always set to 0 in
> InitializeDSMForeignScan(), so that won’t work.  Any other ideas?

At that state it's simply not yet known how many workers will be
actually launched (they might not start successfully or such). Why do
you need to know it there and not later?

- Andres