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
[mac...@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
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