postgresql on FreeBSD 5.3 and high load

[Vlad GALU]

On Wed, 1 Dec 2004 11:51:13 +0100 (CET), Claus Guttesen
<cguttesen at yahoo.dk> wrote:
> Hi.
> 
> Our postgresql-server hits the wall when we get many
> hits on our web. The load-average reaches 70. It
> serves 11 webservers.
> 
> The server is a Dell PE 2850 with 4 GB RAM, dual
> Nocona at 3.2 GHz, HTT is not enabled. It's running
> FreeBSD 5.3 stable (amd64-port). Postgresql ver. 7.4.5
> from ports. The SCSI-controller is LSILogic MegaRAID
> with six disks and three stripes which is mirrored
> (RAID 0+1). Only hardware RAID.
> 
> Due to problems with 4 GB RAM I added hw.physmem=4G to
> /boot/loader.conf, which for some reason reduced
> available memory to 3211 MB. Since then it has run
> stable.
> 
> I have this custom-kernel:
> 
> options         SHMMAXPGS=262144
> options         SEMMNI=160
> options         SEMMNS=960
> options         SEMUME=160
> options         SEMMNU=480
> options         PMAP_SHPGPERPROC=1280
> 
> postgresql.conf:
> 
> max_connections = 768
> shared_buffers = 65536
> sort_mem = 4096
> vacuum_mem = 65536
> checkpoint_segments = 4
> commit_delay = 100000
> commit_siblings = 250
> effective_cache_size = 32768
> 
> Fsync is *not* enabled. I have increased
> shared_buffers and commit_siblings gradually, but it
> does not seem to lower the load on the server.
> 
> /etc/sysctl.conf:
> kern.ipc.somaxconn=2048
> kern.maxfiles=65536
> net.isr.enable=1
> 
> ipcs -M:
> shminfo:
>  shmmax: 1073741824 (max shared memory segment size)
>  shmmin:       1 (min shared memory segment size)
>  shmmni:     192 (max number of shared memory
> identifiers)
>  shmseg:     128 (max shared memory segments per
> process)
>  shmall:  262144 (max amount of shared memory in
> pages)
> 
> Eventhough load average is high, it's not always 0 %
> idle, but between 0 and 2 percent.
> 
> netstat -m

> 18446744073709545011 mbufs in use
    ^^^^^^^^^^^^^^
               ??????

> 4519/25600 mbuf clusters in use (current/max)
> 0/0/0 sfbufs in use (current/peak/max)
> 7386 KBytes allocated to network
> 0 requests for sfbufs denied
> 0 requests for sfbufs delayed
> 0 requests for I/O initiated by sendfile
> 20286 calls to protocol drain routines
> 
> I can't find the bottleneck.
> 
> regards
> Claus
> 
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