Re: pgstat_report_activity() and parallel CREATE INDEX (was: Parallel index creation & pg_stat_activity)

On Sat, Oct 17, 2020 at 08:39:35AM -0700, Peter Geoghegan wrote:
> On Tue, Oct 13, 2020 at 7:26 PM Noah Misch <noah@leadboat.com> wrote:
> > 1. Disable parallelism for the index build under ExecuteTruncateGuts().
> >    Nobody will mourn a performance loss from declining parallelism for an
> >    empty index, but I feel like this is fixing in the wrong place.
> > 2. Make _bt_begin_parallel() and begin_parallel_vacuum() recognize the
> >    debug_query_string==NULL case and reproduce it on the worker.
> > 3. Require bgworkers to set debug_query_string before entering code of vacuum,
> >    truncate, etc.  Logical replication might synthesize a DDL statement, or it
> >    might just use a constant string.
> >
> > I tend to prefer (2), but (3) isn't bad.  Opinions?
> 
> I also prefer 2.

Thanks.  Here is the pair of patches I plan to use.  The second is equivalent
to v0; I just added a log message.