On Mon, May 2, 2016 at 2:44 PM, David G. Johnston <david.g.johns...@gmail.com> wrote: > Does this apply to the extent that a value of 1 is likely worse than 0 since > the leader is now tasked with accumulating but there is only one process > actually working to provide the leader data?
I don't know what that means, but it doesn't work like that. If the worker can't generate data fast enough, the leader will also run the parallel portion of the plan. So 1 is unlikely to be worse than 0; in fact it's often a lot better. > I'm inclined to accept max_parallel_workers where a value of 0 means no > parallelism and the non-zero counts indicate the number of workers in > addition to the required leader. That's how it works now. > Though that does suggest "additional" as a valid option. Something like > "max_additional_workers". Just how overloaded is the term "worker". If > worker is understood to mean "a process which implements execution of [part > of] a query plan" the word additional leaves no ambiguity as to where the > leader is accounted for. > > It does significantly reduce grep-ability though :( > > max_additional_parallel_workers... I don't think that it's likely to be very clear what "additional" refers to in this context. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers