> 28 мая 2016 г., в 0:56, Andres Freund <and...@anarazel.de> написал(а): > > Hi, > > > On 2016-05-27 19:57:34 +0300, Vladimir Borodin wrote: >> -performance >>> Here is how the results look like for 9.4, 9.5 and 9.6. All are built from >>> latest commits on yesterday in >>> * REL9_4_STABLE (a0cc89a28141595d888d8aba43163d58a1578bfb), >>> * REL9_5_STABLE (e504d915bbf352ecfc4ed335af934e799bf01053), >>> * master (6ee7fb8244560b7a3f224784b8ad2351107fa55d). >>> >>> All of them are build on the host where testing is done (with stock gcc >>> versions). Sysctls, pgbouncer config and everything we found are the same, >>> postgres configs are default, PGDATA is in tmpfs. All numbers are >>> reproducible, they are stable between runs. >>> >>> Shortly: >>> >>> OS PostgreSQL version TPS Avg. >>> latency >>> RHEL 6 9.4 44898 >>> 1.425 ms >>> RHEL 6 9.5 26199 >>> 2.443 ms >>> RHEL 6 9.5 43027 >>> 1.487 ms >>> Ubuntu 14.04 9.4 67458 >>> 0.949 ms >>> Ubuntu 14.04 9.5 64065 >>> 0.999 ms >>> Ubuntu 14.04 9.6 64350 >>> 0.995 ms >> >> The results above are not really fair, pgbouncer.ini was a bit different on >> Ubuntu host (application_name_add_host was disabled). Here are the right >> results with exactly the same configuration: >> >> OS PostgreSQL version TPS Avg. >> latency >> RHEL 6 9.4 44898 >> 1.425 ms >> RHEL 6 9.5 26199 >> 2.443 ms >> RHEL 6 9.5 43027 >> 1.487 ms >> Ubuntu 14.04 9.4 45971 1.392 ms >> Ubuntu 14.04 9.5 40282 1.589 ms >> Ubuntu 14.04 9.6 45410 1.409 ms > > Hm. I'm a bit confused. You show one result for 9.5 with bad and one > with good performance. I suspect the second one is supposed to be a 9.6?
No, they are both for 9.5. One of them is on RHEL 6 host, another one on Ubuntu 14.04. > > Am I understanding correctly that the performance near entirely > recovered with 9.6? Yes, 9.6 is much better than 9.5. > If so, I suspect we might be dealing with a memory > alignment issue. Do the 9.5 results change if you increase > max_connections by one or two (without changing anything else)? Results with max_connections=100: OS Version TPS Avg. latency RHEL 6 9.4 69810 0.917 RHEL 6 9.5 35303 1.812 RHEL 6 9.6 71827 0.891 Ubuntu 14.04 9.4 76829 0.833 Ubuntu 14.04 9.5 67574 0.947 Ubuntu 14.04 9.6 79200 0.808 Results with max_connections=101: OS Version TPS Avg. latency RHEL 6 9.4 70059 0.914 RHEL 6 9.5 35979 1.779 RHEL 6 9.6 71183 0.899 Ubuntu 14.04 9.4 78934 0.811 Ubuntu 14.04 9.5 67803 0.944 Ubuntu 14.04 9.6 79624 0.804 Results with max_connections=102: OS Version TPS Avg. latency RHEL 6 9.4 70710 0.905 RHEL 6 9.5 36615 1.748 RHEL 6 9.6 69742 0.918 Ubuntu 14.04 9.4 76356 0.838 Ubuntu 14.04 9.5 66814 0.958 Ubuntu 14.04 9.6 78528 0.815 Doesn’t seem that it is a memory alignment issue. Also please note that there is no performance degradation when connections from pgbench to postgres are established without pgbouncer: OS Version TPS Avg. latency RHEL 6 9.4 167427 0.382 RHEL 6 9.5 223674 0.286 RHEL 6 9.6 215580 0.297 Ubuntu 14.04 9.4 176659 0.362 Ubuntu 14.04 9.5 248277 0.258 Ubuntu 14.04 9.6 245871 0.260 > > What's the actual hardware? Host with RHEL has Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz (2 sockets, 16 physical cores, 32 cores with Hyper-Threading) and 256 GB of RAM while host with Ubuntu has Intel(R) Xeon(R) CPU E5-2667 v2 @ 3.30GHz (2 sockets, 16 physical cores, 32 cores with Hyper-Threading) and 128 GB of RAM. > > Greetings, > > Andres Freund -- May the force be with you… https://simply.name
