On Wed, Jul 4, 2018 at 3:36 PM, Etsuro Fujita
<fujita.etsuro@lab.ntt.co.jp> wrote:
>
> I don't produce a test case where the plan is an Append with Gather
> subplans, but I'm not sure that it's a good thing to allow us to consider
> such a plan because in that plan, each Gather would try to grab its own pool
> of workers. Am I missing something?
If the overall join can not use parallelism, having individual child
joins use parallel query might turn out to be efficient even if done
one child at a time. Parallel append drastically reduces the cases
where something like could be useful, but I don't think we can
theoretically eliminate the need for such a plan.
--
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company
