Re: pg_stat_progress_create_index vs. parallel index builds

On 2021-Jun-02, Tomas Vondra wrote:

> Hi,
> 
> While experimenting with parallel index builds, I've noticed a somewhat
> strange behavior of pg_stat_progress_create_index when a btree index is
> built with parallel workers - some of the phases seem to be missing.

Hmm, that's odd.  I distinctly recall testing the behavior with parallel
workers, and it is mentioned by Rahila in the original thread, and I
think we tried to ensure that it was sane.  I am surprised to learn that
there's such a large gap.

I'll go have a deeper look at the provided patch and try to get it
backpatched.

I think it would be valuable to have some kind of test mode where the
progress reporting APIs would make some noise (perhaps with a bespoke
GUC option) so that we can test things in some automated manner ...

-- 
Álvaro Herrera                            39°49'30"S 73°17'W
"In fact, the basic problem with Perl 5's subroutines is that they're not
crufty enough, so the cruft leaks out into user-defined code instead, by
the Conservation of Cruft Principle."  (Larry Wall, Apocalypse 6)