Re: hint in determining effective_io_concurrency

On Thu, Apr 22, 2021 at 10:22:59PM +0200, Luca Ferrari wrote:
> On Thu, Apr 22, 2021 at 10:15 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
> > Note that the interpretation of this GUC changed in v13.
> > https://www.postgresql.org/docs/13/release-13.html
> > |Change the way non-default effective_io_concurrency values affect concurrency (Thomas Munro)
> > |Previously, this value was adjusted before setting the number of concurrent requests. The value is now used directly. Conversion of old values to new ones can be done using:
> > |SELECT round(sum(OLDVALUE / n::float)) AS newvalue FROM generate_series(1, OLDVALUE) s(n);
>
> Yeah, I know, thanks.
> However, I'm still curious about which tools to use to get info about
> the storage queue/concurrency.

I think you'd run something like iostat -dkx 1 and watch avgqu-sz.

--
Justin