On 11/30/2010 4:34 AM, Gregory Machin wrote:
Hi this is the first time I'm working with Posgresql other than a defualt install. I have a CentOS 5.5 virtual machine with - 4 virtual cpus , 8 Gig RAM , resource pool set to High (8000) running on a vmware ESXi 4.1 host - 4 x 2.4 GHz cpus AMD 6 cores each, 96 Gig ram, storage is provided by HP Left hand SAN iSCSI. I'm running post Postgresql 8.4.4 rpm from the postgresql repo. What I need to clarify is wether the performance issue the website that uses database is experiencing is related to postgresql miss configuration or bad code in the site. Customisations in the postgresql.conf max_connections = 1000 shared_buffers = 4096MB temp_buffers = 512MB work_mem = 10MB # min 64kB maintenance_work_mem = 160MB # min 1MB fsync = off synchronous_commit = on wal_sync_method = open_sync full_page_writes = off effective_cache_size = 32MB join_collapse_limit = 1 autovacuum_vacuum_cost_delay = 100ms checkpoint_segments = 60 this configuration gives the following pgbench results [macgre@topnz15209-linux ~]$ pgbench -h drvppgs01 -U postgres -c 40 -T 120 test starting vacuum...end. transaction type: TPC-B (sort of) scaling factor: 1 query mode: simple number of clients: 40 duration: 120 s number of transactions actually processed: 47070 tps = 391.660580 (including connections establishing) tps = 392.523468 (excluding connections establishing) pgbench was setup with pgbench -h drvppgs01 -U postgres -c 40 -T 120 -i test -F 100 -S 15 mpstat every 5 seconds gives the following:
pgbench needs its scale (-s) and #connections (-c) to be close. You have a scale of 1 and 40 connections, so this is a bad test. Init with -s 40, then run with -c at 40 or less.
Your mpstat output is hard to read because of the word wrapping. Not sure if iostat would be more readable (its usually the one I look at (I'd never even heard of mpstat before now)).
> fsync = off Thats a bad idea if you care about your data. > effective_cache_size = 32MB That looks wrong, you better read up on that one in the docs. -Andy -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
