I have standard 'out-of-the-box' installation of

Linux version 3.0.1.stk64 (dfn@localhost.localdomain) (gcc version 4.5.1 20100924 (Red Hat 4.5.1-4) (GCC) ) #1 SMP Sat Aug 13 12:53:46 EDT 2011

It has postgresql 8.4 installed as (start script)


Data directory


My problem is that sometimes the Kernel decides to kill some of the Postgresql processes at times of low memory. I would like to inform kernel that Postgresql should not be chosen to be killed. I read from postgresql documentation (http://www.postgresql.org/docs/9.1/static/kernel-resources.html) that a command line echo -17 > /proc/self/oom_adj can be used to avoid the kill.

I tried to add this commandline to /etc/init.d/postgresql script but don't really know where to put it there.

Any pointers how to go about it? The scipt (/etc/init.d/postgresql) by the way is:

set -e

# Provides:             postgresql
# Required-Start:       $local_fs $remote_fs $network $time
# Required-Stop:        $local_fs $remote_fs $network $time
# Should-Start:         $syslog
# Should-Stop:          $syslog
# Default-Start:        2 3 4 5
# Default-Stop:         0 1 6
# Short-Description:    PostgreSQL RDBMS server

# Setting environment variables for the postmaster here does not work; please
# set them in /etc/postgresql/<version>/<cluster>/environment instead.

[ -r /usr/share/postgresql-common/init.d-functions ] || exit 0

. /usr/share/postgresql-common/init.d-functions

# versions can be specified explicitly
if [ -n "$2" ]; then
    versions="$2 $3 $4 $5 $6 $7 $8 $9"

case "$1" in
        for v in $versions; do
            $1 $v
        for v in $versions; do
            reload $v
        echo "Usage: $0 {start|stop|restart|reload|force-reload|status} [version ..]"
        exit 1

exit 0

You should adjust oom_adj directly to postmaster pid, add a lines like this (NOT TESTED):

pid=`cat $PGDATA/postmaster.pid | head -1`
echo -17 > /proc/$pid/oom_adj
| improve this answer | |
  • I can confirm that /proc/$postmasterpid/oom_adj default value is zero whereas sshd has -17 on redhat and debian. Shouldn't -17 be the default and a feature request be done? – user130370 Oct 25 '12 at 16:25
  • -17 is default in postgres-9.0 (and 9.1), i think version 8 is using too old init script to adjust oom-killer parameters. – Andrei Mikhaltsov Oct 25 '12 at 16:40
  • BTW oom_adj is obsolete, kernel.org/doc/Documentation/ABI/obsolete/proc-pid-oom_adj – Andrei Mikhaltsov Oct 25 '12 at 16:42
  • Yes oom_score_adj should be used instead, but you need a recent kernel (not avail in rhel5). – user130370 Oct 25 '12 at 16:52
  • NOTE: I am not a Linux guru so I did not understand a single word of advice here .. what can I do to make it work with 8.4 asap and preferably so that it is part of the startup script(s) and works like a charm at automatic startup? – Martin Oct 26 '12 at 4:35

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