Re: BUG #18343: Incorrect description in postgresql.conf for max_parallel_workers_per_gather - Mailing list pgsql-bugs

From Tom Lane
Subject Re: BUG #18343: Incorrect description in postgresql.conf for max_parallel_workers_per_gather
Date
Msg-id 3258900.1708012510@sss.pgh.pa.us
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In response to BUG #18343: Incorrect description in postgresql.conf for max_parallel_workers_per_gather  (PG Bug reporting form <noreply@postgresql.org>)
Responses Re: BUG #18343: Incorrect description in postgresql.conf for max_parallel_workers_per_gather  ("David G. Johnston" <david.g.johnston@gmail.com>)
List 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



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