----- Original Message ----- > From: "Jeff Janes" <jeff.janes@xxxxxxxxx> > To: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx> > Cc: pgsql-performance@xxxxxxxxxxxxxx > Sent: Thursday, September 18, 2014 4:56:22 PM > Subject: Re: postgres 9.3 vs. 9.4 > > On Thu, Sep 18, 2014 at 2:58 AM, Mkrtchyan, Tigran <tigran.mkrtchyan@xxxxxxx > > wrote: > > > > > > > Hi Folk, > > > > I am trying to investigate some performance issues which we have with > > postgres > > (a different topic by itself) and tried postgres.9.4beta2, with a hope > > that it > > perform better. > > > > Turned out that 9.4 is 2x slower than 9.3.5 on the same hardware. > > > > Some technical details: > > > > Host: rhel 6.5 2.6.32-431.23.3.el6.x86_64 > > 256 GB RAM, 40 cores, Intel(R) Xeon(R) CPU E5-2660 v2 @ 2.20GHz > > 2x160GB PCIe SSD DELL_P320h-MTFDGAL175SAH ( on one 9.3, on an other one > > 9.4 ) > > > > Why are the versions segregated that way? Are you sure they are configured > identically? es, they are configured identically > > > > > > postgres tweaks: > > > > > > default_statistics_target = 100 > > wal_writer_delay = 10s > > vacuum_cost_delay = 50 > > synchronous_commit = off > > > > Are you sure that synchronous_commit is actually off on the 9.4 instance? yes, synchronous_commit is off. > > 9.3.5: > > > > # /usr/pgsql-9.3/bin/pgbench -r -j 1 -c 1 -T 60 > > > > ... > > > > 0.035940 END; > > > > > > 9.4beta2: > > > ... > > > 0.957854 END; > > > > Looks like IO. Postgres internal IO? May be. We get 600MB/s on this SSDs. Tigran. > > Cheers, > > Jeff > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
