Re: Parallel INSERT (INTO ... SELECT ...)

On Fri, Oct 9, 2020 at 6:26 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Fri, Oct 9, 2020 at 3:51 PM Greg Nancarrow <gregn4422(at)gmail(dot)com> wrote:
> >
> > On Fri, Oct 9, 2020 at 8:09 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > OK, I will update the comments for this.
> > Basically, up to now, the "force_parallel_mode" has only ever operated
> > on a SELECT.
> > But since we are now allowing CMD_INSERT to be assessed for parallel
> > mode too, we need to prevent the force_parallel_mode logic from
> > sticking a Gather node over the top of arbitrary INSERTs and causing
> > them to be run in parallel. Not all INSERTs are suitable for parallel
> > operation, and also there are further considerations for
> > parallel-safety for INSERTs compared to SELECT. INSERTs can also
> > trigger UPDATEs.
> >
>
> Sure but in that case 'top_plan->parallel_safe' should be false and it
> should stick Gather node atop Insert node.
>

/should/should not.

--
With Regards,
Amit Kapila.