Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation) - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation)
Date
Msg-id CAH2-Wz=eXfYdsFQh2HrqzgfM9TQZa-r13DfwEHYWb0OBg8-HAQ@mail.gmail.com
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In response to Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation)  (Amit Kapila <amit.kapila16@gmail.com>)
Responses Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation)
List pgsql-hackers
On Fri, Jan 19, 2018 at 8:44 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> Right, but I think using parallel_leader_participation, you can do it
> reliably and probably write some regression tests which can complete
> in a predictable time.

Do what reliably? Guarantee that the leader will not participate as a
worker, but that workers will be used? If so, yes, you can get that.

The only issue is that you may not be able to launch parallel workers
due to hitting a limit like max_parallel_workers, in which case you'll
get a serial index build despite everything. Nothing we can do about
that, though.

-- 
Peter Geoghegan


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