Re: Parallel Seq Scan vs kernel read ahead

On Wed, 10 Jun 2020 at 17:21, Thomas Munro <thomas.munro@gmail.com> wrote:
> I also heard from Andres that he likes this patch with his AIO
> prototype, because of the way request merging works.  So it seems like
> there are several reasons to want it.
>
> But ... where should we get the maximum step size from?  A GUC?

I guess we'd need to determine if other step sizes were better under
any conditions.  I guess one condition would be if there was a LIMIT
clause. I could check if setting it to 1024 makes any difference, but
I'm thinking it won't since I got fairly consistent results on all
worker settings with the patched version.

David