Re: High context switches occurring

On Tue, 20 Dec 2005, Tom Lane wrote:

> Oleg Bartunov <oleg@sai.msu.su> writes:
>> I see a very low performance and high context switches on our
>> dual itanium2 slackware box (Linux ptah 2.6.14 #1 SMP)
>> with 8Gb of RAM, running 8.1_STABLE. Any tips here ?
>
>> postgres@ptah:~/cvs/8.1/pgsql/contrib/pgbench$ time pgbench -s 10 -c 10 -t 3000 pgbench
>> starting vacuum...end.
>> transaction type: TPC-B (sort of)
>> scaling factor: 1
>> number of clients: 10
>
> You can't expect any different with more clients than scaling factor :-(.

Argh :) I copy'n pasted from previous message.

I still wondering with very poor performance of my server. Moving
pgdata to RAID6 helped - about 600 tps. Then, I moved pg_xlog to separate
disk and got strange error messages

postgres@ptah:~$ time pgbench  -c 10  -t 3000 pgbench
starting vacuum...end.
Client 0 aborted in state 8: ERROR:  integer out of range
Client 7 aborted in state 8: ERROR:  integer out of range

dropdb,createdb helped, but performance is about 160 tps.

Low-end AMD64 with SATA disks gives me ~400 tps in spite of
disks on itanium2 faster ( 80MB/sec ) than on AMD64 (60MB/sec).


     Regards,
         Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83