Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

View thread
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
Cc: Peter Geoghegan <pg@bowt.ie>, Andres Freund <andres@anarazel.de>, Phil Florent <philflorent@hotmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-10-25T14:52:50Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Set debug_query_string in worker_spi.

  2. Reproduce debug_query_string==NULL on parallel workers.

  3. Logical replication support for TRUNCATE

  4. Call pgstat_report_activity() in parallel CREATE INDEX workers.

Noah Misch <noah@leadboat.com> writes:
> On Sat, Oct 17, 2020 at 08:39:35AM -0700, Peter Geoghegan wrote:
>> 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.

The change in worker_spi_main seems a little weird/lazy.  I'd
be inclined to set and clear debug_query_string each time through
the loop, so that those operations are adjacent to the other
status-reporting operations, as they are in initialize_worker_spi.

I don't really like modifying a StringInfo while debug_query_string
is pointing at it, either.  Yeah, you'll *probably* get away with
that because the buffer is unlikely to move, but since the whole
exercise can only benefit crash-debugging scenarios, it'd be better
to be more paranoid.

One idea is to set debug_query_string immediately before each SPI_execute
and clear it just afterwards, rather than trying to associate it with
pgstat_report_activity calls.

			regards, tom lane