Re: Add new option 'all' to pg_stat_reset_shared()

On Thu, 2 Nov 2023 at 20:26, Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
>
> On Wed, Nov 1, 2023 at 4:24 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
> >
> > On Tue, Oct 31, 2023 at 04:26:18PM +0900, torikoshia wrote:
> > > Yes, calling pg_stat_reset_shared() for all stats types can do what I wanted
> > > to do.
> > > But calling it with 6 different parameters seems tiresome and I thought it
> > > would be convenient to have a parameter to delete all cluster-wide
> > > statistics at once.
> > >
> > > I may be wrong, but I imagine that it's more common to want to delete all of
> > > the statistics for an entire cluster rather than just a portion of it.
> >
> > If more flexibility is wanted in this function, could it be an option
> > to consider a flavor like pg_stat_reset_shared(text[]), where it is
> > possible to specify a list of shared stats types to reset? Perhaps
> > there are no real use cases for it, just wanted to mention it anyway
> > regarding the fact that it could have benefits to refactor this code
> > to use a bitwise operator for its internals with bit flags for each
> > type.
>
> I don't see a strong reason to introduce yet-another API when someone
> can just call things in a loop. I could recollect a recent analogy - a
> proposal to have a way to define multiple custom wait events with a
> single function call instead of callers defining in a loop didn't draw
> much interest.

Knowing that your metrics have a shared starting point can be quite
valuable, as it allows you to do some math that would otherwise be
much less accurate when working with stats over a short amount of
time. I've not used these stats systems much myself, but skew between
metrics caused by different reset points can be difficult to detect
and debug, so I think an atomic call to reset all these stats could be
worth implementing.

Kind regards,

Matthias van de Meent
Neon (https://neon.tech)