Re: pgsql: Add a new GUC and a reloption to enable inserts in parallel-mode

On Wed, Mar 24, 2021 at 8:28 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Wed, Mar 24, 2021 at 2:00 AM Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> >
> > On 2021-Mar-23, Robert Haas wrote:
> >
> > > Likewise, the XXX comment you added to max_parallel_hazard_walker
> > > claims that some of the code introduced there is to compensate for an
> > > unspecified bug in the rewriter. I'm a bit skeptical that the comment
> > > is correct, and there's no way to find out because the comment doesn't
> > > say what the bug supposedly is, but let's just say for the sake of
> > > argument that it's true. Well, you *could* have fixed the bug, but
> > > instead you hacked around it, and in a relatively expensive way that
> > > affects every query with a CTE in it whether it can benefit from this
> > > patch or not. That's not a responsible way of maintaining the core
> > > PostgreSQL code.
> >
> > I think the CTE bug is this one:
> >
> > https://www.postgresql.org/message-id/flat/CAJcOf-fAdj=nDKMsRhQzndm-O13NY4dL6xGcEvdX5Xvbbi0V7g(at)mail(dot)gmail(dot)com
> >
> > while I can't disagree with the overall conclusion that it seems safer
> > to revert parallel INSERT/SELECT given the number of alleged problems,
> >
>
> Agreed. I'll revert the patch and respond to some of the points here
> with my thoughts.
>

BTW, I think the revert needs catversion bump as commit
c5be48f092016b1caf597b2e21d588b56c88a23e has changed catalog. I hope
that is fine but if not do let me know?

--
With Regards,
Amit Kapila.