Re: Parallel Inserts (WAS: [bug?] Missed parallel safety checks..)

On Fri, Jul 30, 2021 at 6:53 PM houzj(dot)fnst(at)fujitsu(dot)com
<houzj(dot)fnst(at)fujitsu(dot)com> wrote:
>
> On Friday, July 30, 2021 2:52 PM Greg Nancarrow <gregn4422(at)gmail(dot)com> wrote:
> > On Fri, Jul 30, 2021 at 4:02 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > > > Besides, I think we need a new default value about parallel dml
> > > > safety. Maybe 'auto' or 'null'(different from
> > > > safe/restricted/unsafe). Because, user is likely to alter the safety
> > > > to the default value to get the automatic safety check, a independent default
> > > > value can make it more clear.
> > > >
> > >
> > > Hmm, but auto won't work for partitioned tables, right? If so, that
> > > might appear like an inconsistency to the user and we need to document
> > > the same. Let me summarize the discussion so far in this thread so
> > > that it is helpful to others.
> > >
> >
> > To avoid that inconsistency, UNSAFE could be the default for partitioned tables
> > (and we would disallow setting AUTO for these).
> > So then AUTO is the default for non-partitioned tables only.
>
> I think this approach is reasonable, +1.
>

I see the need to change to default via Alter Table but I am not sure
if Auto is the most appropriate way to handle that. How about using
DEFAULT itself as we do in the case of REPLICA IDENTITY? So, if users
have to alter parallel safety value to default, they need to just say
Parallel DML DEFAULT. The default would mean automatic behavior for
non-partitioned relations and ignore parallelism for partitioned
tables.

--
With Regards,
Amit Kapila.