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

On Thu, Jan 11, 2018 at 3:25 PM, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> On Thu, Jan 11, 2018 at 12:06 PM, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
>> It might make sense to have the "minimum memory per participant" value
>> come from a GUC, rather than be hard coded (it's currently hard-coded
>> to 32MB).
>
>> What do you think of that idea?
>
> A third option here is to specifically recognize that
> compute_parallel_worker() returned a value based on the table storage
> param max_workers, and for that reason alone no "insufficient memory
> per participant" decrementing/vetoing should take place. That is, when
> the max_workers param is set, perhaps it should be completely
> impossible for CREATE INDEX to ignore it for any reason other than an
> inability to launch parallel workers (though that could be due to the
> max_parallel_workers GUC's setting).
>
> You could argue that we should do this anyway, I suppose.

Yes, I think this sounds like a good idea.

--
Robert Haas
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