On Tue, May 24, 2016 at 1:38 PM, Ants Aasma <ants.aa...@eesti.ee> wrote: >> I've already observed such behavior, see [1]. I think that now there is no >> consensus on how to fix that. For instance, Andres express opinion that >> this shouldn't be fixed from LWLock side [2]. >> FYI, I'm planning to pickup work on CSN patch [3] for 10.0. CSN should fix >> various scalability issues including high ProcArrayLock contention. > > Some amount of non-fairness is ok, but degrading to the point of > complete denial of service is not very graceful. I don't think it's > realistic to hope that all lwlock contention issues will be fixed any > time soon. Some fallback mechanism would be extremely nice until then.
Jim Gray's paper on the "Convoy phenomenon" remains relevant, decades later: http://www.msr-waypoint.com/en-us/um/people/gray/papers/Convoy%20Phenomenon%20RJ%202516.pdf I could believe that there's a case to be made for per-LWLock fairness characteristics, which may be roughly what Andres meant. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
