Re: BUG #18343: Incorrect description in postgresql.conf for max_parallel_workers_per_gather

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: kline.christopher@gmail.com
Cc: pgsql-bugs@lists.postgresql.org
Date: 2024-02-15T15:55:10Z
Lists: pgsql-bugs
PG Bug reporting form <noreply@postgresql.org> writes:
> In the default postgresql.conf that is generated, there are the following
> lines:

> #max_worker_processes = 8		# (change requires restart)
> #max_parallel_workers_per_gather = 2	# taken from max_parallel_workers 
> <<<<<<<<<<<<<<<<<<<<<<<< THIS
> #max_parallel_maintenance_workers = 2	# taken from max_parallel_workers
> max_parallel_workers = 8		# maximum number of max_worker_processes that
> 					# can be used in parallel operations

> it indicates that the default value is taken from whatever
> max_parallel_workers is.

No, you're misreading it.  There's no magic connection between these
two settings.  What the comment means to say is that the per-gather
worker processes come out of a pool of at most max_parallel_workers
processes.  Perhaps another wording would be better, but we don't have
a lot of space here --- any thoughts?

			regards, tom lane



Commits

  1. Doc: improve a couple of comments in postgresql.conf.sample.