Re: Parallel Seq Scan vs kernel read ahead

On Sat, 23 May 2020 at 06:31, Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Thu, May 21, 2020 at 6:28 PM Thomas Munro <thomas.munro@gmail.com> wrote:
> > Right, I think it's safe.  I think you were probably right that
> > ramp-up isn't actually useful though, it's only the end of the scan
> > that requires special treatment so we don't get unfair allocation as
> > the work runs out, due to course grain.
>
> The ramp-up seems like it might be useful if the query involves a LIMIT.

That's true, but I think the intelligence there would need to go
beyond, "if there's a LIMIT clause, do ramp-up", as we might have
already fully ramped up well before the LIMIT is reached.

David