Better script to restart mysql on Ubuntu 8.04 - mysql

Question

When I say sudo /etc/init.d/mysql restart on Ubuntu 8.04.2 sometimes there remains a mysql_safe process eating 99% of cpu. Making the machine practically unusable.
Is there a better way to restart mysql? I thought about writing a script:
sudo /etc/init.d/mysql stop
sleep 10
sudo killall mysql_safe
sudo /etc/init.d/mysql start
But this would be a evil workaround. (And the script is just a quick shot)
I googled and found that mysql_safe is a wrapper script which starts mysqld, and makes sure it gets restarted if it should die. So there should be a better way to restart the thing.
I googled that this is a common problem in this ubuntu version. Is Debian / Ubuntu doing it wrong at this point? The /etc/init.d script looks quite sophisticated, and it deals with mysql_safe also, but my skills are not good enough to understand it fully. But this would be the best place to improve. This is a paste of the version on my machine (which is untouched):
#!/bin/bash
#
### BEGIN INIT INFO
# Provides: mysql
# Required-Start: $remote_fs $syslog mysql-ndb
# Required-Stop: $remote_fs $syslog mysql-ndb
# Should-Start: $network $named $time
# Should-Stop: $network $named $time
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start and stop the mysql database server daemon
# Description: Controls the main MySQL database server daemon "mysqld"
# and its wrapper script "mysqld_safe".
### END INIT INFO
#
set -e
set -u
${DEBIAN_SCRIPT_DEBUG:+ set -v -x}
test -x /usr/sbin/mysqld || exit 0
. /lib/lsb/init-functions
SELF=$(cd $(dirname $0); pwd -P)/$(basename $0)
CONF=/etc/mysql/my.cnf
MYADMIN="/usr/bin/mysqladmin --defaults-file=/etc/mysql/debian.cnf"
# priority can be overriden and "-s" adds output to stderr
ERR_LOGGER="logger -p daemon.err -t /etc/init.d/mysql -i"
# Safeguard (relative paths, core dumps..)
cd /
umask 077
# mysqladmin likes to read /root/.my.cnf. This is usually not what I want
# as many admins e.g. only store a password without a username there and
# so break my scripts.
export HOME=/etc/mysql/
## Fetch a particular option from mysql's invocation.
#
# Usage: void mysqld_get_param option
mysqld_get_param() {
/usr/sbin/mysqld --print-defaults \
| tr " " "\n" \
| grep -- "--$1" \
| tail -n 1 \
| cut -d= -f2
}
## Do some sanity checks before even trying to start mysqld.
sanity_checks() {
# check for config file
if [ ! -r /etc/mysql/my.cnf ]; then
log_warning_msg "$0: WARNING: /etc/mysql/my.cnf cannot be read. See README.Debian.gz"
echo "WARNING: /etc/mysql/my.cnf cannot be read. See README.Debian.gz" | $ERR_LOGGER
fi
# check for diskspace shortage
datadir=`mysqld_get_param datadir`
if LC_ALL=C BLOCKSIZE= df --portability $datadir/. | tail -n 1 | awk '{ exit ($4>4096) }'; then
log_failure_msg "$0: ERROR: The partition with $datadir is too full!"
echo "ERROR: The partition with $datadir is too full!" | $ERR_LOGGER
exit 1
fi
}
## Checks if there is a server running and if so if it is accessible.
#
# check_alive insists on a pingable server
# check_dead also fails if there is a lost mysqld in the process list
#
# Usage: boolean mysqld_status [check_alive|check_dead] [warn|nowarn]
mysqld_status () {
ping_output=`$MYADMIN ping 2>&1`; ping_alive=$(( ! $? ))
ps_alive=0
pidfile=`mysqld_get_param pid-file`
if [ -f "$pidfile" ] && ps `cat $pidfile` >/dev/null 2>&1; then ps_alive=1; fi
if [ "$1" = "check_alive" -a $ping_alive = 1 ] ||
[ "$1" = "check_dead" -a $ping_alive = 0 -a $ps_alive = 0 ]; then
return 0 # EXIT_SUCCESS
else
if [ "$2" = "warn" ]; then
echo -e "$ps_alive processes alive and '$MYADMIN ping' resulted in\n$ping_output\n" | $ERR_LOGGER -p daemon.debug
fi
return 1 # EXIT_FAILURE
fi
}
#
# main()
#
case "${1:-''}" in
'start')
sanity_checks;
# Start daemon
log_daemon_msg "Starting MySQL database server" "mysqld"
if mysqld_status check_alive nowarn; then
log_progress_msg "already running"
log_end_msg 0
else
/usr/bin/mysqld_safe > /dev/null 2>&1 &
# 6s was reported in #352070 to be too few when using ndbcluster
for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14; do
sleep 1
if mysqld_status check_alive nowarn ; then break; fi
log_progress_msg "."
done
if mysqld_status check_alive warn; then
log_end_msg 0
# Now start mysqlcheck or whatever the admin wants.
output=$(/etc/mysql/debian-start)
[ -n "$output" ] && log_action_msg "$output"
else
log_end_msg 1
log_failure_msg "Please take a look at the syslog"
fi
fi
# Some warnings
if $MYADMIN variables | egrep -q have_bdb.*YES; then
echo "BerkeleyDB is obsolete, see /usr/share/doc/mysql-server-5.0/README.Debian.gz" | $ERR_LOGGER -p daemon.info
fi
if [ -f /etc/mysql/debian-log-rotate.conf ]; then
echo "/etc/mysql/debian-log-rotate.conf is obsolete, see /usr/share/doc/mysql-server-5.0/NEWS.Debian.gz" | $ERR_L
fi
;;
'stop')
# * As a passwordless mysqladmin (e.g. via ~/.my.cnf) must be possible
# at least for cron, we can rely on it here, too. (although we have
# to specify it explicit as e.g. sudo environments points to the normal
# users home and not /root)
log_daemon_msg "Stopping MySQL database server" "mysqld"
if ! mysqld_status check_dead nowarn; then
set +e
shutdown_out=`$MYADMIN shutdown 2>&1`; r=$?
set -e
if [ "$r" -ne 0 ]; then
log_end_msg 1
[ "$VERBOSE" != "no" ] && log_failure_msg "Error: $shutdown_out"
log_daemon_msg "Killing MySQL database server by signal" "mysqld"
killall -15 mysqld
server_down=
for i in 1 2 3 4 5 6 7 8 9 10; do
sleep 1
if mysqld_status check_dead nowarn; then server_down=1; break; fi
done
if test -z "$server_down"; then killall -9 mysqld; fi
fi
fi
if ! mysqld_status check_dead warn; then
log_end_msg 1
log_failure_msg "Please stop MySQL manually and read /usr/share/doc/mysql-server-5.0/README.Debian.gz!"
exit -1
else
log_end_msg 0
fi
;;
'restart')
set +e; $SELF stop; set -e
$SELF start
;;
'reload'|'force-reload')
log_daemon_msg "Reloading MySQL database server" "mysqld"
$MYADMIN reload
log_end_msg 0
;;
'status')
if mysqld_status check_alive nowarn; then
log_action_msg "$($MYADMIN version)"
else
log_action_msg "MySQL is stopped."
exit 3
fi
;;
*)
echo "Usage: $SELF start|stop|restart|reload|force-reload|status"
exit 1
;;
esac
I found many hints, but I would like this resolved to a certain degree of reliability for production servers.
Edit: It seems to be exactly this unsolved bug.
Maybe it is this bug from the MySQL site.
This seems related or identical.
Some people talk of a race condition with 2 instances of mysql_safe. Others suggest commentiong out the sanity check in the startup script.

Answer 1

I would try to figure out what is causing the CPU issue, rather than investigate how to re-write the startup script. The startup script is fairly standard and should work well in a production environment.