mysqld_safe脚本

 

 

#!/bin/sh // 脚本开头一定要以这么一行开头吗？ // 这个脚本用于启动MySQL进程，如果它意外死亡，可以重新启动这个进程，如何做到，使用一个监听进程?起看门狗的作用? # # This should be executed in the MySQL base directory if you are using a # binary installation that has other paths than you are using. # # mysql.server works by first doing a cd to the base directory and from there # executing mysqld_safe KILL_MYSQLD=1; MYSQLD= trap '' 1 2 3 15 # we shouldn't let anyone kill us umask 007 defaults= case "$1" in --no-defaults|--defaults-file=*|--defaults-extra-file=*) defaults="$1"; shift ;; esac usage () { cat < /dev/null 2>&1 then normal_niceness=`nice` nohup_niceness=`nohup nice` numeric_nice_values=1 for val in $normal_niceness $nohup_niceness do case "$val" in -[0-9] | -[0-9][0-9] | -[0-9][0-9][0-9] | / [0-9] | [0-9][0-9] | [0-9][0-9][0-9] ) ;; * ) numeric_nice_values=0 ;; esac done if test $numeric_nice_values -eq 1 then nice_value_diff=`expr $nohup_niceness - $normal_niceness` if test $? -eq 0 && test $nice_value_diff -gt 0 && / nice --$nice_value_diff echo testing > /dev/null 2>&1 then # nohup increases the priority (bad), and we are permitted # to lower the priority with respect to the value the user # might have been given niceness=`expr $niceness - $nice_value_diff` NOHUP_NICENESS="nice -$niceness nohup" fi fi else if nohup echo testing > /dev/null 2>&1 then : else # nohup doesn't work on this system NOHUP_NICENESS="" fi fi USER_OPTION="" if test -w / -o "$USER" = "root" then if test "$user" != "root" -o $SET_USER = 1 then USER_OPTION="--user=$user" fi # If we are root, change the err log to the right user. touch $err_log; chown $user $err_log if test -n "$open_files" then ulimit -n $open_files args="--open-files-limit=$open_files $args" fi fi # Try to set the core file size (even if we aren't root) because many systems # don't specify a hard limit on core file size. if test -n "$core_file_size" then ulimit -c $core_file_size fi # # If there exists an old pid file, check if the daemon is already running # Note: The switches to 'ps' may depend on your operating system if test -f $pid_file then PID=`cat $pid_file` if /bin/kill -0 $PID > /dev/null 2> /dev/null then if /bin/ps p $PID | grep -v grep | grep $MYSQLD > /dev/null then # The pid contains a mysqld process echo "A mysqld process already exists" echo "A mysqld process already exists at " `date` >> $err_log exit 1 fi fi rm -f $pid_file if test -f $pid_file then echo "Fatal error: Can't remove the pid file: $pid_file" echo "Fatal error: Can't remove the pid file: $pid_file at " `date` >> $err_log echo "Please remove it manually and start $0 again" echo "mysqld daemon not started" exit 1 fi fi # # Uncomment the following lines if you want all tables to be automatically # checked and repaired during startup. You should add sensible key_buffer # and sort_buffer values to my.cnf to improve check performance or require # less disk space. # Alternatively, you can start mysqld with the "myisam-recover" option. See # the manual for details. # # echo "Checking tables in $DATADIR" # $MY_BASEDIR_VERSION/bin/myisamchk --silent --force --fast --medium-check $DATADIR/*/*.MYI # $MY_BASEDIR_VERSION/bin/isamchk --silent --force $DATADIR/*/*.ISM echo "Starting $MYSQLD daemon with databases from $DATADIR" # Does this work on all systems? #if type ulimit | grep "shell builtin" > /dev/null #then # ulimit -n 256 > /dev/null 2>&1 # Fix for BSD and FreeBSD systems #fi echo "`date +'%y%m%d %H:%M:%S mysqld started'`" >> $err_log while true do rm -f $safe_mysql_unix_port $pid_file # Some extra safety if test -z "$args" then $NOHUP_NICENESS $ledir/$MYSQLD $defaults --basedir=$MY_BASEDIR_VERSION --datadir=$DATADIR $USER_OPTION --pid-file=$pid_file --skip-external-locking >> $err_log 2>&1 else eval "$NOHUP_NICENESS $ledir/$MYSQLD $defaults --basedir=$MY_BASEDIR_VERSION --datadir=$DATADIR $USER_OPTION --pid-file=$pid_file --skip-external-locking $args >> $err_log 2>&1" fi if test ! -f $pid_file # This is removed if normal shutdown then echo "STOPPING server from pid file $pid_file" break fi if true && test $KILL_MYSQLD -eq 1 then # Test if one process was hanging. # This is only a fix for Linux (running as base 3 mysqld processes) # but should work for the rest of the servers. # The only thing is ps x => redhat 5 gives warnings when using ps -x. # kill -9 is used or the process won't react on the kill. numofproces=`ps xaww | grep -v "grep" | grep "$ledir/$MYSQLD/>" | grep -c "pid-file=$pid_file"` echo -e "/nNumber of processes running now: $numofproces" | tee -a $err_log I=1 while test "$I" -le "$numofproces" do PROC=`ps xaww | grep "$ledir/$MYSQLD/>" | grep -v "grep" | grep "pid-file=$pid_file" | sed -n '$p'` for T in $PROC do break done # echo "TEST $I - $T **" if kill -9 $T then echo "$MYSQLD process hanging, pid $T - killed" | tee -a $err_log else break fi I=`expr $I + 1` done fi echo "`date +'%y%m%d %H:%M:%S'` mysqld restarted" | tee -a $err_log done echo "`date +'%y%m%d %H:%M:%S'` mysqld ended" | tee -a $err_log echo "" | tee -a $err_log