Re: postgresql + apache under heavy load

Hello Richard,
Thank you for your answer.
Richard Huxton wrote:

>Are you saying you had more than 8 connections open simultaneously?
>
Well, I don't know how to find that out.
What I did is issuing several tomes a ps aux and I never saw more than
6-7 postmaster SELECT.

>Are you
>sure you restarted PG so that it noticed the new values? You can check config
>settings with "show all;" from psql, or "show <setting>".
>
Yes I restart it. The show command outputs the correct value (8).

>
>You'll want to use the "top" command to show the amount of memory each process
>

A typical output (in a concurrency of 20, no cache) is:
ps aux | grep postgres
postgres 2332 0.0 0.0 8804 328 ? R 18:54 0:01
/usr/bin/postmaster -p 5432 -d2
postgres 2334 0.0 0.0 9792 68 ? S 18:54 0:00 postgres:
stats buffer process
postgres 2335 0.0 0.0 8828 200 ? S 18:54 0:00 postgres:
stats collector process
postgres 4386 0.0 0.2 4312 956 pts/3 S 19:22 0:00 -bash
postgres 4871 0.0 0.5 9480 2304 ? S 20:36 0:00 postgres:
user db [local] SELECT
postgres 4873 0.0 0.2 8816 1032 ? R 20:36 0:00 postgres:
user db [local] startup
myuser 4877 0.0 0.1 3572 624 pts/4 S 20:36 0:00 grep postgres
postgres 4878 0.0 0.5 9220 2228 ? R 20:36 0:00 postgres:
user db [local] SELECT
postgres 4879 0.0 0.5 9204 2016 ? R 20:36 0:00 postgres:
user db [local] SELECT
---------------------------top-----------------------------
114 processes: 99 sleeping, 12 running, 3 zombie, 0 stopped
CPU states: 91.8% user 8.1% system 0.0% nice 0.0% iowait 0.0% idle
Mem: 384580k av, 316328k used, 68252k free, 0k shrd, 25424k
buff
253976k actv, 36916k in_d, 4704k in_c
Swap: 265064k av, 64788k used, 200276k free 71132k
cached

PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND
4914 apache 16 0 9016 8416 2552 S 6.7 2.1 0:00 0 httpd
4832 apache 16 0 9016 8416 2552 S 6.3 2.1 0:01 0 httpd
4915 apache 16 0 9016 8416 2552 S 5.9 2.1 0:00 0 httpd
4917 apache 16 0 9016 8416 2552 S 5.9 2.1 0:00 0 httpd
4919 apache 16 0 9020 8420 2536 S 5.9 2.1 0:00 0 httpd
4774 apache 16 0 9016 8416 2552 S 5.7 2.1 0:02 0 httpd
4896 apache 16 0 9060 8460 2568 S 5.7 2.1 0:00 0 httpd
4908 apache 15 0 9016 8416 2552 S 5.7 2.1 0:00 0 httpd
4909 apache 16 0 9016 8416 2552 S 5.7 2.1 0:00 0 httpd
4658 apache 16 0 9136 8536 2568 S 5.5 2.2 0:04 0 httpd
4921 apache 16 0 9016 8416 2552 S 5.5 2.1 0:00 0 httpd
2581 root 16 0 14492 4544 1252 R 5.3 1.1 2:26 0 X
4795 apache 16 0 9104 8504 2568 S 5.3 2.2 0:02 0 httpd
4796 apache 16 0 9080 8480 2568 S 5.3 2.2 0:01 0 httpd
4782 apache 16 0 8924 8324 2568 R 3.5 2.1 0:02 0 httpd
2612 madona 15 0 4524 4136 2380 S 1.5 1.0 0:18 0 metacity
4656 apache 15 0 9084 8484 2568 S 1.3 2.2 0:03 0 httpd
4950 postgres 25 0 0 0 0 Z 1.1 0.0 0:00 0
postmaster <defunct>
3812 madona 15 0 44728 42M 17460 S 0.7 11.2 3:21 0
mozilla-bin
4947 postgres 25 0 2540 2392 1688 S 0.7 0.6 0:00 0 postmaster
4952 postgres 25 0 2812 2664 1872 R 0.7 0.6 0:00 0 postmaster
4610 madona 15 0 7460 7460 2152 R 0.5 1.9 0:00 0 xterm
4904 madona 15 0 1108 1108 856 R 0.3 0.2 0:00 0 top
4954 postgres 24 0 1916 1768 1244 R 0.1 0.4 0:00 0 postmaster
4959 postgres 25 0 1596 1448 940 S 0.1 0.3 0:00 0 postmaster
4961 postgres 25 0 984 824 640 R 0.1 0.2 0:00 0 postmaster
1 root 15 0 88 60 40 S 0.0 0.0 0:04 0 init

Thanks
Alex