On Thu, Jun 6, 2024 at 7:20 PM Michael Paquier <michael@paquier.xyz> wrote:
> On Thu, Jun 06, 2024 at 09:48:51AM -0400, Robert Haas wrote:
> > It's not this patch set's fault, but I'm not very pleased to see that
> > the injection point wait events have been shoehorned into the
> > "Extension" category - which they are not - instead of being a new
> > wait_event_type. That would have avoided the ugly wait-event naming
> > pattern, inconsistent with everything else, introduced by
> > inplace050-tests-inj-v1.patch.
>
> Not sure to agree with that. The set of core backend APIs supporting
> injection points have nothing to do with wait events. The library
> attached to one or more injection points *may* decide to use a wait
> event like what the wait/wakeup calls in modules/injection_points do,
> but that's entirely optional. These rely on custom wait events,
> plugged into the Extension category as the code run is itself in an
> extension. I am not arguing against the point that it may be
> interesting to plug in custom wait event categories, but the current
> design of wait events makes that much harder than what core is
> currently able to handle, and I am not sure that this brings much at
> the end as long as the wait event strings can be customized.
>
> I've voiced upthread concerns over the naming enforced by the patch
> and the way it plugs the namings into the isolation functions, by the
> way.
I think the core code should provide an "Injection Point" wait event
type and let extensions add specific wait events there, just like you
did for "Extension". Then this ugly naming would go away. As I see it,
"Extension" is only supposed to be used as a catch-all when we have no
other information, but here we do. If we refuse to use the
wait_event_type field to categorize waits, then people are going to
have to find some other way to get that data into the system, as Noah
has done.
--
Robert Haas
EDB: http://www.enterprisedb.com