Re: pg_stat_io not tracking smgrwriteback() is confusing

Hi,

On 2023-04-24 10:52:15 +0530, Amit Kapila wrote:
> On Sun, Apr 23, 2023 at 12:55 AM Jonathan S. Katz <jkatz@postgresql.org> wrote:
> > > I wonder if it's
> > > worth doing so for 16? It'd give a more complete picture that way. The
> > > counter-argument I see is that we didn't track the time for it in existing
> > > stats either, and that nobody complained - but I suspect that's mostly because
> > > nobody knew to look.
> >
> > [RMT hat]
> >
> > (sorry for slow reply on this, I've been out for a few days).
> >
> > It does sound generally helpful to track writeback to ensure anyone
> > building around pg_stat_io can see tthe more granular picture. How big
> > of an effort is this?
> >
> 
> Right, I think this is the key factor to decide whether we can get
> this in PG16 or not. If this is just adding a new column and a few
> existing stats update calls then it should be okay to get in but if
> this requires some more complex work then we can probably update the
> docs.

I suspect it should really just be adding a few stats calls. The only possible
complication that I can see is that we might need to pass a bit more context
down in a place or two.

Greetings,

Andres Freund