On Mon, Jun 28, 2010 at 1:12 PM, Craig James <craig_james@xxxxxxxxxxxxxx> wrote: > On 6/25/10 12:03 PM, Greg Smith wrote: >> >> Craig James wrote: >>> >>> I've got a new server and want to make sure it's running well. >> >> Any changes to the postgresql.conf file? Generally you need at least a >> moderate shared_buffers (1GB or so at a minimum) and checkpoint_segments >> (32 or higher) in order for the standard pgbench test to give good >> results. > > max_connections = 500 > shared_buffers = 1000MB > work_mem = 128MB > synchronous_commit = off > full_page_writes = off > wal_buffers = 256kB > checkpoint_segments = 30 > effective_cache_size = 4GB > > For fun I ran it with the installation defaults, and it never got above 1475 > TPS. > >>> pgbench -c20 -t 5000 -U test >>> tps = 5789 >>> pgbench -c30 -t 3333 -U test >>> tps = 6961 >>> pgbench -c40 -t 2500 -U test >>> tps = 2945 >> >> General numbers are OK, the major drop going from 30 to 40 clients is >> larger than it should be. I'd suggest running the 40 client count one >> again to see if that's consistent. > > It is consistent. When I run pgbench from a different server, I get this: > > pgbench -c40 -t 2500 -U test > tps = 7999 > > pgbench -c100 -t 1000 -U test > tps = 6693 6k tps over 8 7200 rpm disks is quite good imo. synchronous_commit setting is making that possible. building a server that could handle that much was insanely expensive just a few years ago, on relatively cheap sorage. that's 21m transactions an hour or ~ half a billion transactions a day (!). running this kind of load 24x7 on postgres 7.x would have been an enormous headache. how quickly we forget! :-) your 'real' tps write, 1475 tps, spread over 4 disks doing the actual writing, is giving you ~ 370 tps/device. not bad at all -- the raid controller is doing a good job (the raw drive might get 200 or so). I bet performance will be somewhat worse with a higher scaling factor (say, 500) because there is less locality of writes -- something to consider if you expect your database to get really big. merlin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
