On Sun, Sep 10, 2017 at 5:29 AM, Dmitry Dolgov <9erthali...@gmail.com> wrote: > average latency: > > clients patch master > 10 0.321 0.286 > 20 0.669 0.602 > 30 1.016 0.942 > 40 1.358 1.280 > 50 1.727 1.637
That's still a noticeable slowdown, though. And we've had previous reports of the overhead of logging being significant as well: http://postgr.es/m/caclsapsa7u0gcfpojvqem6sgtekv8vnwdbfhvi+dqo+gu5g...@mail.gmail.com I seem to recall a discussion, perhaps in-person, around the time Theo submitted that patch where it was reported that the logging collector could not be used on some systems he was working with because it became a major performance bottleneck. With each backend writing its own messages to a file, it was tolerable, but when you tried to funnel everything through a single process, the back-pressure slowed down the entire system unacceptably. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
