On Tue, Aug 18, 2015 at 8:01 AM, Michael H <mich...@wemoto.com> wrote:
> Hi, > > I've been tuning our new database server, here's some info... > > CentOS Linux release 7.1.1503 (Core) > 3.10.0-229.11.1.el7.x86_64 > > 8 x 16GB 1600MHz PC3-12800 DDR3 - 128GB total > 2 x AMD Opteron 6386SE 2.8GHz/16-core/140w - 32 cores total > 4 x 300GB SAS 10k HDD - raid 1+0 configuration > 1GB FBWC for P-series smart array - cache enabled > > I'm using the CentOS provided packages for PostgreSQL > Version : 9.2.13 > Release : 1.el7_1 > > I'm getting fairly good statistics from this server but after asking for > some advice I was pointed towards PostgreSQL 9.3 (posix memory management) > and PostgreSQL 9.4 (pg_replication_slots). > > I dropped my original install of 9.2.13 above and went straight to the 9.4 > from the PostgreSQL repositories. > How did you get your data from 9.2 to 9.4? Did you run ANALYZE on it afterwards? > Are there any known issues with my kernel and PostgreSQL? I found this > post - > > http://www.databasesoup.com/2014/09/why-you-need-to-avoid-linux-kernel-32.html > > which states there are known issues up to kernel 3.10.. the reason I ask, > no matter how small or big a configuration change I make I can't match my > 9.2.13 install. I'm seeing huge decreases in TPS on all my benchmarks. > > for example, 9.2.13, my own extremely heavy SQL file being used here, > hence the lower TPS... > > 32 37.357197 > 64 34.145088 > 128 19.682544 > 256 9.910772 > 512 5.803358 > > compared to 9.4 - exactly the same tests and parameters configured (I also > started from defaults and tuned up as best I could). > > 32 14.982111 > 64 14.894859 > 128 14.277631 > 256 13.679516 > 512 13.679516 > Pick the query that dropped in performance the most, then run it with "explain (analyze, buffers)" and with track_io_timing turned on, and compare this between the servers. Did the plan change, or just the time? Cheers, Jeff
