Re: Run-time pruning for ModifyTable

Kato-san,

On Thu, Jul 4, 2019 at 1:40 PM Kato, Sho <kato-sho(at)jp(dot)fujitsu(dot)com> wrote:
> > If I understand the details of [1] correctly, ModifyTable will no longer
> > have N subplans for N result relations as there are today. So, it doesn't
> > make sense for ModifyTable to contain PartitionedRelPruneInfos and for
> > ExecInitModifyTable/ExecModifyTable
> > to have to perform initial and execution-time pruning, respectively.
>
> Does this mean that the generic plan will not have N subplans for N result relations?
> I thought [1] would make creating generic plans faster, but is this correct?

Yeah, making a generic plan for UPDATE of inheritance tables will
certainly become faster, because we will no longer plan the same query
N times for N child tables. There will still be N result relations
but only one sub-plan to fetch the rows from. Also, planning will
still cost O(N), but with a much smaller constant factor.

By the way, let's keep any further discussion on this particular topic
in the other thread.

Thanks,
Amit