understanding postgres issues/bottlenecks - Mailing list pgsql-performance

Hi list,
I would like to ask your help in order to understand if my postgresql
server (ver. 8.2.9) is well configured.
It's a quad-proc system (32 bit) with a 6 disk 1+0 RAID array and 2
separate disks for the OS and write-ahead logs with 4GB of RAM.

I don't know what is the best info to help me and so I start with some
vmstat information:

 > vmstat -n 30
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy
id wa st
 0 23     84 129968  25060 3247860    0    0    78    50    0    2 17  5
33 45  0
 1 24     84 124204  25136 3257100    0    0  3037  1154 3359 7253 25
7  6 62  0
 2 30     84 124704  25136 3256344    0    0  3004  1269 3553 7906 33
9  7 51  0
 0 25     84 125784  24956 3253344    0    0  3357   773 3163 6454 17  4
10 68  0
 0  2     84 125744  25236 3258996    0    0  3186   567 3125 6425 24  6
21 50  0
 3  7     84 124948  25500 3260088    0    0  1829   535 2706 4625 18  3
54 25  0
 5  0     84 124976  25624 3259112    0    0  2067   647 3050 6163 26  6
41 27  0
 0  7     84 123836  25644 3260760    0    0  2239  1065 3289 8654 27  7
38 28  0

These are gathered loadavg info for the same period:
29.57 29.53 33.52 1/231 12641
29.54 29.63 33.31 1/226 12678
24.43 28.45 32.69 1/223 12696
12.31 24.17 30.95 4/223 12706

At the moment as average there are about 120/150 connections and this is
my postgresql.conf file

listen_addresses = '*'                  # what IP address(es) to listen on;
port = 5432                             # (change requires restart)
max_connections = 400                   # (change requires restart)
ssl = off                               # (change requires restart)
password_encryption = on
shared_buffers = 32MB                   # min 128kB or max_connections*16kB
max_prepared_transactions = 0           # can be 0 or more
work_mem = 1MB                          # min 64kB
maintenance_work_mem = 256MB            # min 1MB
max_fsm_pages = 204800                  # min max_fsm_relations*16, 6
bytes each
fsync = on                              # turns forced synchronization
on or off
full_page_writes = on                   # recover from partial page writes
wal_buffers = 8MB                       # min 32kB
checkpoint_segments = 56                # in logfile segments, min 1,
16MB each
enable_bitmapscan = on
enable_hashagg = on
enable_hashjoin = on
enable_indexscan = on
enable_mergejoin = on
enable_nestloop = on
enable_seqscan = on
enable_sort = on
enable_tidscan = on
cpu_tuple_cost = 0.003                  # same scale as above
cpu_index_tuple_cost = 0.001            # same scale as above
cpu_operator_cost = 0.0005              # same scale as above
effective_cache_size = 3GB
geqo_threshold = 14
log_destination = 'stderr'              # Valid values are combinations of
redirect_stderr = on                    # Enable capturing of stderr
into log
log_directory = 'pg_log'                # Directory where log files are
written
log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' # Log file name pattern.
log_truncate_on_rotation = on           # If on, any existing log file
of the same
log_rotation_age = 1d                   # Automatic rotation of logfiles
will
log_rotation_size = 0                   # Automatic rotation of logfiles
will
log_min_duration_statement = -1         # -1 is disabled, 0 logs all
statements
log_statement = 'none'                  # none, ddl, mod, all

autovacuum = on                         # enable autovacuum subprocess?
stats_start_collector = on              # must be 'on' for autovacuum
stats_row_level = on                    # must be 'on' for autovacuum

statement_timeout = 150000
datestyle = 'iso, mdy'
lc_messages = 'en_US.UTF-8'                     # locale for system
error message
lc_monetary = 'en_US.UTF-8'                     # locale for monetary
formatting
lc_numeric = 'en_US.UTF-8'                      # locale for number
formatting
lc_time = 'en_US.UTF-8'                         # locale for time formatting
deadlock_timeout = 5s
escape_string_warning = off
standard_conforming_strings = on


Cheers and thanks a lot in advance.
Let me know if other info is useful.
Ste

--
Stefano Nichele

Funambol Chief Architect
Funambol :: Open Source Mobile'We' for the Mass Market :: http://www.funambol.com