Обсуждение: [PERFORM] How does max_parallel_workers_per_gather change load averages?
Hello,
This is my first question on this list.
How does max_parallel_workers_per_gather change Linux server load averages?
I have 2 cores and my max_parallel_workers_per_gather = 2 and max_worker_processes = 8, but my load averages are between 8 and 5 with scheduled at 1/189 to 5/195. Are these so high because I increased max_parallel_workers_per_gather? My understanding is that if my load averages are greater than my number of cores the system is overloaded. Should I think about it differently once I increase max_parallel_workers_per_gather? How should I think about it?
I am using postgres 9.6.
On 4 October 2017 at 08:48, Ben Nachtrieb <bnachtrieb@crescat.net> wrote: > I have 2 cores and my max_parallel_workers_per_gather = 2 and > max_worker_processes = 8, but my load averages are between 8 and 5 with > scheduled at 1/189 to 5/195. Are these so high because I increased > max_parallel_workers_per_gather? My understanding is that if my load > averages are greater than my number of cores the system is overloaded. > Should I think about it differently once I increase > max_parallel_workers_per_gather? How should I think about it? Parallel query is not 100% efficient. For example, adding twice the CPU, in theory, will never double the performance, there's always some overhead to this. It's really only useful to do on systems with spare CPU cycles to perform this extra work. You don't seem to have much to spare, so you may get along better if you disable parallel query. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance