Re: pg13dev: explain partial, parallel hashagg, and memory use

On Wed, 5 Aug 2020 at 14:13, Justin Pryzby <pryzby@telsasoft.com> wrote:
> Also odd (to me).  If I encourage more workers, there are "slots" for each
> "planned" worker, even though fewer were launched:

Looking at explain.c for "num_workers; " (including the final space at
the end), looking at each for loop that loops over each worker, quite
a number of those locations have a condition that skips the worker.

For example, show_sort_info() does

if (sinstrument->sortMethod == SORT_TYPE_STILL_IN_PROGRESS)
continue; /* ignore any unfilled slots */

So maybe Hash Agg should be doing something similar.  Additionally,
maybe it should not show the leader details if the leader didn't help.

David