Re: [HACKERS] CLUSTER command progress monitor

On Tue, Mar 5, 2019 at 3:56 AM Tatsuro Yamada
<yamada(dot)tatsuro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> >> === Discussion points ===
> >>
> >> - Progress counter for "3. sorting tuples" phase
> >> - Should we add pgstat_progress_update_param() in tuplesort.c like a
> >> "trace_sort"?
> >> Thanks to Peter Geoghegan for the useful advice!
> >
> > How would we avoid an abstraction violation?
>
> Hmm... What do you mean an abstraction violation?
> If it is difficult to solve, I'd not like to add the progress counter for the sorting tuples.

What I mean is... I think it would be useful to have this counter, but
I'm not sure how the tuplesort code would know to update the counter
in this case and not in other cases. The tuplesort code is used for
lots of things; we can't update a counter for CLUSTER if the tuplesort
is being used for CREATE INDEX or a Sort node in a query or whatever.
So my question is how we would indicate to the tuplesort that it needs
to do the counter update, and whether that would end up making for
ugly code.

--
Robert Haas
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