Re: crashes due to setting max_parallel_workers=0

Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Mar 27, 2017 at 1:29 AM, Rushabh Lathia
> <rushabh.lathia@gmail.com> wrote:
>> But it seems a bit futile to produce the parallel plan in the first place,
>> because with max_parallel_workers=0 we can't possibly get any parallel
>> workers ever. I wonder why compute_parallel_worker() only looks at
>> max_parallel_workers_per_gather, i.e. why shouldn't it do:
>> parallel_workers = Min(parallel_workers, max_parallel_workers);
>> Perhaps this was discussed and is actually intentional, though.

> It was intentional.  See the last paragraph of
> https://www.postgresql.org/message-id/CA%2BTgmoaMSn6a1780VutfsarCu0LCr%3DCO2yi4vLUo-JQbn4YuRA@mail.gmail.com

Since this has now come up twice, I suggest adding a comment there
that explains why we're intentionally ignoring max_parallel_workers.
        regards, tom lane