Re: Rename max_parallel_degree?
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Peter Geoghegan <pg@heroku.com>
Cc: Josh berkus <josh@agliodbs.com>, Robert Haas <robertmhaas@gmail.com>,
Noah Misch <noah@leadboat.com>,
David Rowley <david.rowley@2ndquadrant.com>,
Amit Kapila <amit.kapila16@gmail.com>,
Alvaro Herrera <alvherre@2ndquadrant.com>,
Magnus Hagander <magnus@hagander.net>,
Bruce Momjian <bruce@momjian.us>,
PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2016-05-31T18:08:57Z
Lists: pgsql-hackers
Peter Geoghegan <pg@heroku.com> writes: > Even when the leader is consuming input from workers, that's still perhaps > pegging one CPU core. So, it doesn't really invalidate what I said about > the number of cores being the primary consideration. Agreed, but if we think that people need to be thinking in those terms, maybe the parameter should be "max_parallel_cores". The alternate docs patch I just posted tries to deal with this by describing max_parallel_workers as being the max number of worker processes used to "assist" a parallel query. That was terminology already being used in one place, but not consistently. If we use it consistently, I think it would be sufficient to remind people that they need to figure on one more core for the leader. regards, tom lane