Re: [HACKERS] posmaster failed under high load

On Wed, 5 May 1999, Tom Lane wrote:

> Date: Wed, 05 May 1999 09:33:14 -0400
> From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
> To: Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>
> Cc: hackers(at)postgreSQL(dot)org
> Subject: Re: [HACKERS] posmaster failed under high load
>
> Oleg Bartunov <oleg(at)sai(dot)msu(dot)su> writes:
> > That's why I noticed 10 or more (postmaster) processes, which eventually
> > gone after 30-40 minutes.
>
> Could those be new backends that have been forked off the main
> postmaster, but haven't yet gotten around to changing their ps info?
> I'm not sure what would block a new backend for many minutes before
> it did that, however. Can you attach to one of these processes with
> a debugger and get a backtrace to show what it's doing?

Well,

http_load -r 40 -f 240 MASON-DBI
results:
244 fetches, 1020 max parallel, 272060 bytes, in 52 seconds
1115 mean bytes/connection
4.69231 fetches/sec, 5231.92 bytes/sec

Below some output from ps and attached backtrace of one postmaster
process.

Regards,

Oleg

PS.
Will see what happens with those (postmasters)

18:08[om]:~/app/www/http_load>w
6:09pm up 1:44, 3 users, load average: 44.92, 18.56, 7.08

18:08[om]:/usr/local/etc/httpd/conf>psg post
76 ? S 0:00 postmaster -i -B 1024 -S -D/usr/local/pgsql/data/ -o -Fe
602 ? SW 0:00 (postmaster)
634 ? D 0:00 /usr/local/pgsql/bin/postgres localhost httpd apod idle
644 ? SW 0:00 (postmaster)
646 ? SW 0:00 (postmaster)
648 ? SW 0:00 (postmaster)
650 ? SW 0:00 (postmaster)
651 ? SW 0:00 (postmaster)
652 ? SW 0:00 (postmaster)
653 ? SW 0:00 (postmaster)
661 ? SW 0:00 (postmaster)
662 ? D 0:00 (postmaster)
663 ? SW 0:00 (postmaster)
664 ? SW 0:00 (postmaster)
665 ? D 0:00 (postmaster)
666 ? D 0:00 /usr/local/pgsql/bin/postgres localhost httpd apod idle
18:08[om]:/usr/local/etc/httpd/conf>psg post
76 ? S 0:00 postmaster -i -B 1024 -S -D/usr/local/pgsql/data/ -o -Fe
651 ? SW 0:00 (postmaster)
693 ? SW 0:00 (postmaster)
694 ? SW 0:00 (postmaster)
698 ? S 0:00 /usr/local/pgsql/bin/postgres localhost httpd apod idle
699 ? SW 0:00 (postmaster)
700 ? S 0:00 /usr/local/pgsql/bin/postgres localhost httpd apod idle
701 ? SW 0:00 (postmaster)
702 ? SW 0:00 (postmaster)
18:31[om]:/usr/local/etc/httpd/conf>psg post
76 ? S 0:00 postmaster -i -B 1024 -S -D/usr/local/pgsql/data/ -o -Fe
651 ? SW 0:00 (postmaster)
693 ? SW 0:00 (postmaster)
694 ? SW 0:00 (postmaster)
698 ? S 0:00 /usr/local/pgsql/bin/postgres localhost httpd apod idle
699 ? SW 0:00 (postmaster)
700 ? S 0:00 /usr/local/pgsql/bin/postgres localhost httpd apod idle
701 ? SW 0:00 (postmaster)
702 ? SW 0:00 (postmaster)
18:34[om]:/usr/local/etc/httpd/conf>

om:~$ gdb 702
GDB is free software and you are welcome to distribute copies of it
under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for details.
GDB 4.16 (i486-slackware-linux),
Copyright 1996 Free Software Foundation, Inc...

702: No such file or directory.

(gdb) q
om:~$ gdb /usr/local/pgsql/bin/postmaster 702
GDB is free software and you are welcome to distribute copies of it
under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for details.
GDB 4.16 (i486-slackware-linux),
Copyright 1996 Free Software Foundation, Inc...

/u/postgres/702: No such file or directory.
Attaching to program /usr/local/pgsql/bin/postmaster', process 702
Reading symbols from /lib/libdl.so.1...done.
Reading symbols from /lib/libm.so.5...done.
Reading symbols from /lib/libtermcap.so.2...done.
Reading symbols from /lib/libc.so.5...done.
Reading symbols from /lib/ld-linux.so.1...done.
0x40081464 in recv (sockfd=0, buffer=0xbfffa394, len=3221224256,
flags=135555648)
(gdb) bt
#0 0x40081464 in recv (sockfd=0, buffer=0xbfffa394, len=3221224256,
flags=135555648)
#1 0x400a58e8 in __DTOR_END__ ()
#2 0x80a2585 in pq_getbytes ()
#3 0x80e1ed8 in SocketBackend ()
#4 0x80e1f66 in ReadCommand ()
#5 0x80e350c in PostgresMain ()
#6 0x80ccf2a in DoBackend ()
#7 0x80cca5b in BackendStartup ()
#8 0x80cc1d7 in ServerLoop ()
#9 0x80cbd63 in PostmasterMain ()
#10 0x80a3059 in main ()
#11 0x806121e in _start ()
(gdb)

>
> regards, tom lane
>

_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83