8.2.1 on FreeBSD 5.4-RELEASE - Mailing list pgsql-performance

Hi Guys.


We are running v8.1.2 on FreeBSD 5.4-RELEASE and the server is running
with above averege load.

When i do top i see alot of postmaster processes in "sbwait" state:

# uptime
4:29PM  up 23 days, 20:01, 3 users, load averages: 3.73, 1.97, 1.71

# top
82808 pgsql       1   4    0 15580K 12008K sbwait 0 107:06  7.52%
postgres
82804 pgsql       1   4    0 15612K 12028K sbwait 0 106:13  7.08%
postgres
82806 pgsql       1   4    0 15576K 12008K sbwait 0 106:07  6.84%
postgres
82793 pgsql       1   4    0 15576K 12008K sbwait 0 106:05  6.54%
postgres
82801 pgsql       1   4    0 15612K 12032K sbwait 0 106:13  5.57%
postgres
82800 pgsql       1   4    0 15580K 12012K sbwait 0 105:45  4.88%
postgres
 6613 pgsql       1   4    0 15612K 12020K sbwait 0  28:47  4.59%
postgres
82798 pgsql       1   4    0 15612K 12036K sbwait 0 106:10  4.49%
postgres
82799 pgsql       1   4    0 15612K 12036K sbwait 0 106:27  4.39%
postgres
82797 pgsql       1   4    0 15612K 12036K sbwait 1 106:23  4.25%
postgres
82748 pgsql       1   4    0 15564K 11864K sbwait 0  48:12  3.08%
postgres
82747 pgsql       1   4    0 15560K 11848K sbwait 0  47:58  3.08%
postgres
82749 pgsql       1   4    0 15564K 11868K sbwait 0  48:27  1.95%
postgres
82751 pgsql       1   4    0 15564K 11864K sbwait 0  48:14  1.66%
postgres
82739 pgsql       1   4    0 15564K 11868K sbwait 1  48:38  1.37%
postgres
82750 pgsql       1   4    0 15564K 11864K sbwait 0  48:07  1.27%
postgres


The server is not very busy, but it has more or less as many writes as
reads.

I have not seen more then 10-15 simultaneous queries.


Any idea why idle postmaster consume 3-5% CPU ?

This is a FreeBSD 5.4-RELEASE server with 2x3G Xeon CPUs, 2G memory,
RAID1 mirrored U320 drives.


Thanx
Paul