Still problems with memory swapping and server load

Hi!

I'm still "being hosed over big time" as Curt Sampson put it. It's still
the same machine and database: 1GB RAM, 4xPIII550Xeon, dumpall.sql is
~300MB (see "[GENERAL] Urgent: Tuning strategies?"). It all starts with
a humble 8MB swap being used (I expect that's just the empty swap with
nothing in it but some system overhead). Then after a short time, memory
usage climbs slow but continuously until it hits physical RAM ceiling
and starts using swap - with not very nice results for the database.
Swap sometimes amounts to 200MB or more.

I altered postgresql.conf-settings as recommended:

max_connections = 128
shared_buffers = 32768
sort_mem = 8192 (16384 or 32768 didn't help either)
wal_files = 32
wal_buffers = 32
fsync = false

Everything else is commented out resp. on default settings.

This is what top gives me:
2:41pm up 6 days, 3:51, 3 users, load average: 4.41, 2.71, 1.89
114 processes: 105 sleeping, 9 running, 0 zombie, 0 stopped
CPU0 states: 60.2% user, 14.3% system, 0.0% nice, 24.5% idle
CPU1 states: 81.0% user, 14.5% system, 0.0% nice, 4.0% idle
CPU2 states: 77.0% user, 12.3% system, 0.0% nice, 10.2% idle
CPU3 states: 71.1% user, 13.3% system, 0.0% nice, 15.0% idle
Mem: 1029400K av, 1023264K used, 6136K free, 0K shrd, 7176K
buff
Swap: 2097136K av, 49656K used, 2047480K free 819052K
cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
6848 postgres 16 0 247M 247M 246M R 93.6 24.6 4:06 postmaster
6928 postgres 9 0 13836 13M 13016 S 25.8 1.3 0:13 postmaster
6926 postgres 9 0 14572 14M 13756 S 23.8 1.4 0:13 postmaster
6920 postgres 10 0 14296 13M 13476 R 21.1 1.3 0:13 postmaster
6874 postgres 9 0 49408 48M 43168 S 19.8 4.7 3:57 postmaster
6911 postgres 9 0 66840 65M 65728 S 19.4 6.4 0:01 postmaster
6917 postgres 9 0 9108 9104 8204 R 19.4 0.8 0:13 postmaster
6875 postgres 11 0 41564 40M 35324 R 18.7 4.0 3:31 postmaster
6927 postgres 10 0 14148 13M 13328 R 17.4 1.3 0:12 postmaster
6889 postgres 9 0 24844 24M 23632 S 15.8 2.4 0:17 postmaster
6903 postgres 12 0 204M 204M 203M R 10.2 20.3 0:27 postmaster
6837 postgres 9 0 251M 251M 250M S 9.8 25.0 0:37 postmaster
5929 postgres 15 0 940 884 668 R 8.9 0.0 8:23 top
6934 root 16 0 976 976 732 R 8.0 0.0 0:07 top
6852 postgres 9 0 227M 227M 226M R 7.8 22.6 0:12 postmaster
6897 postgres 9 0 14988 14M 13948 S 6.0 1.4 0:01 postmaster
6838 postgres 9 0 18364 17M 17304 S 5.6 1.7 0:04 postmaster
6845 postgres 9 0 52344 51M 50916 S 3.6 5.0 0:09 postmaster
6834 postgres 9 0 25456 24M 24356 S 3.0 2.4 0:26 postmaster
6894 postgres 9 0 247M 247M 246M S 2.1 24.6 0:27 postmaster
6907 postgres 9 0 16020 15M 14992 S 1.8 1.5 0:03 postmaster
6904 postgres 9 0 16604 16M 15528 S 1.0 1.6 0:13 postmaster
4799 root 9 0 1820 1444 1300 S 0.1 0.1 0:07 sshd
6893 postgres 9 0 18396 17M 17332 S 0.1 1.7 0:07 postmaster
6916 postgres 9 0 8940 8936 8020 S 0.1 0.8 0:08 postmaster

cat /proc/sys/kernel/shmmax is 323380838 and ipcs -m returns:
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status

0x00000000 32768 root 600 1056768 3 dest

0x00000000 98305 root 600 33554432 3 dest

0x00000000 131074 wwwrun 600 368644 3 dest

0x0052e2c1 2457603 postgres 600 274554880 54

0x07021999 229380 root 644 1104 2

Any ideas? Some other way out than "get more RAM"? How effective can I
expect more RAM to be in my situation - wouldn't it just clutter up and
overflow into swap like the first 1GB? How come system-processingtime
gets so high? I followed the other suggestions and tracked slow queries
using logging - now there's hardly anything left with >0.5s execution
time elapsed, but the backends still seem to run amok.

As always very greatful for any help.

Regardy,

Markus