On 05/31/2016 10:03 AM, Tom Lane wrote: > Josh berkus <j...@agliodbs.com> writes: >> I realize there's a lot of water under the bridge here, but I think >> we're going to get 1000 questions on -general of the type: "I asked for >> 8 parallel workers, why did I only get 7?". I believe we will regret >> this change. >> So, one vote from me to revert. > > Well, that gets back to the question of whether average users will > understand the "degree" terminology. For the record, while I do not > like the current behavior either, this was not the solution I favored. > I thought we should rename the GUC and keep it as meaning the number > of additional worker processes.
I will happily bet anyone a nice dinner in Ottawa that most users will not understand it. Compare this: "max_parallel is the maximum number of parallel workers which will work on each stage of the query which is parallizable. If you set it to 4, you get up to 4 workers." with this: "max_parallel_degree is the amount of parallelism in the query, with the understanding that the original parent process counts as 1, which means that if you set it to 1 you get no parallelism, and if you want 4 parallel workers you need to set it to 5." Which one of those is going to require more explanations on -general and -novice? Bets? Let's not be complicated for the sake of being complicated. -- -- Josh Berkus Red Hat OSAS (any opinions are my own) -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers