很多童鞋在启动mysql的时刻,碰到过这个毛病,
起首,廓清一点,涌现这个毛病的前提是:经由历程效劳脚原本启动mysql。经由历程mysqld_safe或mysqld启动mysql实例并不会报这个毛病。
那末,涌现这个毛病的缘由细致是什么呢?
哈哈,对剖析历程不care的童鞋可直接跳到文末的总结部份~
总结
下面,来剖析下mysql的效劳启动剧本
剧本完全内容以下:
#!/bin/sh # Copyright Abandoned 1996 TCX DataKonsult AB & Monty Program KB & Detron HB # This file is public domain and comes with NO WARRANTY of any kind # MySQL daemon start/stop script. # Usually this is put in /etc/init.d (at least on machines SYSV R4 based # systems) and linked to /etc/rc3.d/S99mysql and /etc/rc0.d/K01mysql. # When this is done the mysql server will be started when the machine is # started and shut down when the systems goes down. # Comments to support chkconfig on RedHat Linux # chkconfig: 2345 64 36 # description: A very fast and reliable SQL database engine. # Comments to support LSB init script conventions ### BEGIN INIT INFO # Provides: mysql # Required-Start: $local_fs $network $remote_fs # Should-Start: ypbind nscd ldap ntpd xntpd # Required-Stop: $local_fs $network $remote_fs # Default-Start: 2 3 4 5 # Default-Stop: 0 1 6 # Short-Description: start and stop MySQL # Description: MySQL is a very fast and reliable SQL database engine. ### END INIT INFO # If you install MySQL on some other places than /usr/local/mysql, then you # have to do one of the following things for this script to work: # # - Run this script from within the MySQL installation directory # - Create a /etc/my.cnf file with the following information: # [mysqld] # basedir=<path-to-mysql-installation-directory> # - Add the above to any other configuration file (for example ~/.my.ini) # and copy my_print_defaults to /usr/bin # - Add the path to the mysql-installation-directory to the basedir variable # below. # # If you want to affect other MySQL variables, you should make your changes # in the /etc/my.cnf, ~/.my.cnf or other MySQL configuration files. # If you change base dir, you must also change datadir. These may get # overwritten by settings in the MySQL configuration files. basedir= datadir= # Default value, in seconds, afterwhich the script should timeout waiting # for server start. # Value here is overriden by value in my.cnf. # 0 means don't wait at all # Negative numbers mean to wait indefinitely service_startup_timeout=900 # Lock directory for RedHat / SuSE. lockdir='/var/lock/subsys' lock_file_path="$lockdir/mysql" # The following variables are only set for letting mysql.server find things. # Set some defaults mysqld_pid_file_path= if test -z "$basedir" then basedir=/usr/local/mysql bindir=/usr/local/mysql/bin if test -z "$datadir" then datadir=/usr/local/mysql/data fi sbindir=/usr/local/mysql/bin libexecdir=/usr/local/mysql/bin else bindir="$basedir/bin" if test -z "$datadir" then datadir="$basedir/data" fi sbindir="$basedir/sbin" libexecdir="$basedir/libexec" fi # datadir_set is used to determine if datadir was set (and so should be # *not* set inside of the --basedir= handler.) datadir_set= # # Use LSB init script functions for printing messages, if possible # lsb_functions="/lib/lsb/init-functions" if test -f $lsb_functions ; then . $lsb_functions else log_success_msg() { echo " SUCCESS! $@" } log_failure_msg() { echo " ERROR! $@" } fi PATH="/sbin:/usr/sbin:/bin:/usr/bin:$basedir/bin" export PATH mode=$1 # start or stop [ $# -ge 1 ] && shift other_args="$*" # uncommon, but needed when called from an RPM upgrade action # Expected: "--skip-networking --skip-grant-tables" # They are not checked here, intentionally, as it is the resposibility # of the "spec" file author to give correct arguments only. case `echo "testing\c"`,`echo -n testing` in *c*,-n*) echo_n= echo_c= ;; *c*,*) echo_n=-n echo_c= ;; *) echo_n= echo_c='\c' ;; esac parse_server_arguments() { for arg do case "$arg" in --basedir=*) basedir=`echo "$arg" | sed -e 's/^[^=]*=//'` bindir="$basedir/bin" if test -z "$datadir_set"; then datadir="$basedir/data" fi sbindir="$basedir/sbin" libexecdir="$basedir/libexec" ;; --datadir=*) datadir=`echo "$arg" | sed -e 's/^[^=]*=//'` datadir_set=1 ;; --pid-file=*) mysqld_pid_file_path=`echo "$arg" | sed -e 's/^[^=]*=//'` ;; --service-startup-timeout=*) service_startup_timeout=`echo "$arg" | sed -e 's/^[^=]*=//'` ;; esac done } wait_for_pid () { verb="$1" # created | removed pid="$2" # process ID of the program operating on the pid-file pid_file_path="$3" # path to the PID file. i=0 avoid_race_condition="by checking again" while test $i -ne $service_startup_timeout ; do case "$verb" in 'created') # wait for a PID-file to pop into existence. test -s "$pid_file_path" && i='' && break ;; 'removed') # wait for this PID-file to disappear test ! -s "$pid_file_path" && i='' && break ;; *) echo "wait_for_pid () usage: wait_for_pid created|removed pid pid_file_path" exit 1 ;; esac # if server isn't running, then pid-file will never be updated if test -n "$pid"; then if kill -0 "$pid" 2>/dev/null; then : # the server still runs else # The server may have exited between the last pid-file check and now. if test -n "$avoid_race_condition"; then avoid_race_condition="" continue # Check again. fi # there's nothing that will affect the file. log_failure_msg "The server quit without updating PID file ($pid_file_path)." return 1 # not waiting any more. fi fi echo $echo_n ".$echo_c" i=`expr $i + 1` sleep 1 done if test -z "$i" ; then log_success_msg return 0 else log_failure_msg return 1 fi } # Get arguments from the my.cnf file, # the only group, which is read from now on is [mysqld] if test -x ./bin/my_print_defaults then print_defaults="./bin/my_print_defaults" elif test -x $bindir/my_print_defaults then print_defaults="$bindir/my_print_defaults" elif test -x $bindir/mysql_print_defaults then print_defaults="$bindir/mysql_print_defaults" else # Try to find basedir in /etc/my.cnf conf=/etc/my.cnf print_defaults= if test -r $conf then subpat='^[^=]*basedir[^=]*=\(.*\)$' dirs=`sed -e "/$subpat/!d" -e 's//\1/' $conf` for d in $dirs do d=`echo $d | sed -e 's/[ ]//g'` if test -x "$d/bin/my_print_defaults" then print_defaults="$d/bin/my_print_defaults" break fi if test -x "$d/bin/mysql_print_defaults" then print_defaults="$d/bin/mysql_print_defaults" break fi done fi # Hope it's in the PATH ... but I doubt it test -z "$print_defaults" && print_defaults="my_print_defaults" fi # # Read defaults file from 'basedir'. If there is no defaults file there # check if it's in the old (depricated) place (datadir) and read it from there # extra_args="" if test -r "$basedir/my.cnf" then extra_args="-e $basedir/my.cnf" else if test -r "$datadir/my.cnf" then extra_args="-e $datadir/my.cnf" fi fi parse_server_arguments `$print_defaults $extra_args mysqld server mysql_server mysql.server` # # Set pid file if not given # if test -z "$mysqld_pid_file_path" then mysqld_pid_file_path=$datadir/`hostname`.pid else case "$mysqld_pid_file_path" in /* ) ;; * ) mysqld_pid_file_path="$datadir/$mysqld_pid_file_path" ;; esac fi case "$mode" in 'start') # Start daemon # Safeguard (relative paths, core dumps..) cd $basedir echo $echo_n "Starting MySQL" if test -x $bindir/mysqld_safe then # Give extra arguments to mysqld with the my.cnf file. This script # may be overwritten at next upgrade. $bindir/mysqld_safe --datadir="$datadir" --pid-file="$mysqld_pid_file_path" $other_args >/dev/null 2>&1 & wait_for_pid created "$!" "$mysqld_pid_file_path"; return_value=$? # Make lock for RedHat / SuSE if test -w "$lockdir" then touch "$lock_file_path" fi exit $return_value else log_failure_msg "Couldn't find MySQL server ($bindir/mysqld_safe)" fi ;; 'stop') # Stop daemon. We use a signal here to avoid having to know the # root password. if test -s "$mysqld_pid_file_path" then mysqld_pid=`cat "$mysqld_pid_file_path"` if (kill -0 $mysqld_pid 2>/dev/null) then echo $echo_n "Shutting down MySQL" kill $mysqld_pid # mysqld should remove the pid file when it exits, so wait for it. wait_for_pid removed "$mysqld_pid" "$mysqld_pid_file_path"; return_value=$? else log_failure_msg "MySQL server process #$mysqld_pid is not running!" rm "$mysqld_pid_file_path" fi # Delete lock for RedHat / SuSE if test -f "$lock_file_path" then rm -f "$lock_file_path" fi exit $return_value else log_failure_msg "MySQL server PID file could not be found!" fi ;; 'restart') # Stop the service and regardless of whether it was # running or not, start it again. if $0 stop $other_args; then $0 start $other_args else log_failure_msg "Failed to stop running server, so refusing to try to start." exit 1 fi ;; 'reload'|'force-reload') if test -s "$mysqld_pid_file_path" ; then read mysqld_pid < "$mysqld_pid_file_path" kill -HUP $mysqld_pid && log_success_msg "Reloading service MySQL" touch "$mysqld_pid_file_path" else log_failure_msg "MySQL PID file could not be found!" exit 1 fi ;; 'status') # First, check to see if pid file exists if test -s "$mysqld_pid_file_path" ; then read mysqld_pid < "$mysqld_pid_file_path" if kill -0 $mysqld_pid 2>/dev/null ; then log_success_msg "MySQL running ($mysqld_pid)" exit 0 else log_failure_msg "MySQL is not running, but PID file exists" exit 1 fi else # Try to find appropriate mysqld process mysqld_pid=`pidof $libexecdir/mysqld` # test if multiple pids exist pid_count=`echo $mysqld_pid | wc -w` if test $pid_count -gt 1 ; then log_failure_msg "Multiple MySQL running but PID file could not be found ($mysqld_pid)" exit 5 elif test -z $mysqld_pid ; then if test -f "$lock_file_path" ; then log_failure_msg "MySQL is not running, but lock file ($lock_file_path) exists" exit 2 fi log_failure_msg "MySQL is not running" exit 3 else log_failure_msg "MySQL is running but PID file could not be found" exit 4 fi fi ;; *) # usage basename=`basename "$0"` echo "Usage: $basename {start|stop|restart|reload|force-reload|status} [ MySQL server options ]" exit 1 ;; esac exit 0
起首,定义相干参数
basedir= datadir= # Default value, in seconds, afterwhich the script should timeout waiting # for server start. # Value here is overriden by value in my.cnf. # 0 means don't wait at all # Negative numbers mean to wait indefinitely service_startup_timeout=900 # Lock directory for RedHat / SuSE. lockdir='/var/lock/subsys' lock_file_path="$lockdir/mysql"
个中,
basedir 指的二进制压缩包解压后地点的目次,比如/usr/local/mysql。
datadir 指的是数据目次
service_startup_timeout=900 定义mysql效劳启动的时候限定,假如在900s中没有启动胜利,则该剧本会退出。
lockdir='/var/lock/subsys'
关于/var/lock/subsys,网上的诠释以下,后续会用到。
总的来说,体系封闭的历程(发出封闭信号,挪用效劳本身的历程)中会搜检/var/lock/subsys下的文件,一一封闭每一个效劳,假如某一运转的效劳在/var/lock/subsys下没有响应的选项。在体系封闭的时刻,会像杀死一般历程一样杀死这个效劳。
经由历程观察/etc/rc.d/init.d下的剧本,能够发明每一个效劳本身支配时都邑去检察/var/lock/subsys下响应的效劳。
很多顺序需要推断是不是当前已有一个实例在运转,这个目次就是让顺序推断是不是有实例运转的标志,比如说xinetd,假如存在这个文件,示意已有xinetd在运转了,不然就是没有,固然顺序内里还要有响应的推断步伐来真正肯定是不是有实例在运转。一般与该目次配套的另有/var/run目次,用来寄存对应实例的PID,假如你写剧本的话,会发明这2个目次结合起来能够很轻易的推断出很多效劳是不是在运转,运转的相干信息等等。
推断basedir和datadir
# Set some defaults mysqld_pid_file_path= if test -z "$basedir" then basedir=/usr/local/mysql bindir=/usr/local/mysql/bin if test -z "$datadir" then datadir=/usr/local/mysql/data fi sbindir=/usr/local/mysql/bin libexecdir=/usr/local/mysql/bin else bindir="$basedir/bin" if test -z "$datadir" then datadir="$basedir/data" fi sbindir="$basedir/sbin" libexecdir="$basedir/libexec" fi
个中,
mysqld_pid_file_path 指定pid文件的途径
-z string 推断字符串是不是为空
假如basedir没有显现设置,则默以为/usr/local/mysql,这也是为何很多mysql装置教程都引荐将mysql相干文件放到/usr/local/mysql下。
假如datadir没有显现设置,则默以为$basedir/data。
定义log_success_msg()和log_failure_msg()函数
起首,推断/lib/lsb/init-functions文件是不是存在,假如存在,则使定义在init-functions文件中的一切shell函数在当前剧本中见效。
假如没有,则定义两个函数,一个用于打印胜利日记,一个是打印毛病日记。
在RHCS 6.7中,该文件并不存在,已被/etc/init.d/functions所替换。
# # Use LSB init script functions for printing messages, if possible # lsb_functions="/lib/lsb/init-functions" if test -f $lsb_functions ; then . $lsb_functions else log_success_msg() { echo " SUCCESS! $@" } log_failure_msg() { echo " ERROR! $@" } fi
通报参数
将第一个参数通报给mode,剩下的参数通报给other_args
PATH="/sbin:/usr/sbin:/bin:/usr/bin:$basedir/bin" export PATH mode=$1 # start or stop [ $# -ge 1 ] && shift other_args="$*" # uncommon, but needed when called from an RPM upgrade action # Expected: "--skip-networking --skip-grant-tables" # They are not checked here, intentionally, as it is the resposibility # of the "spec" file author to give correct arguments only. case `echo "testing\c"`,`echo -n testing` in *c*,-n*) echo_n= echo_c= ;; *c*,*) echo_n=-n echo_c= ;; *) echo_n= echo_c='\c' ;; esac
剖析设置文件中的参数
这个函数在剧本后面会触及到。
重要触及以下参数:--basedir,--datadir,--pid-file,--service-startup-timeout。
parse_server_arguments() { for arg do case "$arg" in --basedir=*) basedir=`echo "$arg" | sed -e 's/^[^=]*=//'` bindir="$basedir/bin" if test -z "$datadir_set"; then datadir="$basedir/data" fi sbindir="$basedir/sbin" libexecdir="$basedir/libexec" ;; --datadir=*) datadir=`echo "$arg" | sed -e 's/^[^=]*=//'` datadir_set=1 ;; --pid-file=*) mysqld_pid_file_path=`echo "$arg" | sed -e 's/^[^=]*=//'` ;; --service-startup-timeout=*) service_startup_timeout=`echo "$arg" | sed -e 's/^[^=]*=//'` ;; esac done }
推断my_print_defaults的位置
起首,它推断当前途径下的bin目次中是不是存在该可实行文件,假如不存在,则再推断$bindir(一般指的是$basedir/bin)目次下是不是存在。
假如照样没有,则会推断/etc/my.cnf是不是存在而且可读,假如是,则推断该设置文件中是不是指定了basedir参数,
假如指定了,则掏出该参数的值,并推断该值对应的目次中是不是存在bin/my_print_defaults可实行文件
末了一步,假如在上述目次中着实没发明my_print_defaults文件,
干脆就将print_defaults设置为"my_print_defaults",寄希望于该敕令在当前的PATH环境中。
# Get arguments from the my.cnf file, # the only group, which is read from now on is [mysqld] if test -x ./bin/my_print_defaults then print_defaults="./bin/my_print_defaults" elif test -x $bindir/my_print_defaults then print_defaults="$bindir/my_print_defaults" elif test -x $bindir/mysql_print_defaults then print_defaults="$bindir/mysql_print_defaults" else # Try to find basedir in /etc/my.cnf conf=/etc/my.cnf print_defaults= if test -r $conf then subpat='^[^=]*basedir[^=]*=\(.*\)$' dirs=`sed -e "/$subpat/!d" -e 's//\1/' $conf` for d in $dirs do d=`echo $d | sed -e 's/[ ]//g'` if test -x "$d/bin/my_print_defaults" then print_defaults="$d/bin/my_print_defaults" break fi if test -x "$d/bin/mysql_print_defaults" then print_defaults="$d/bin/mysql_print_defaults" break fi done fi # Hope it's in the PATH ... but I doubt it test -z "$print_defaults" && print_defaults="my_print_defaults" fi
查找默许的设置文件
-r file 假如文件可读,则为真
# # Read defaults file from 'basedir'. If there is no defaults file there # check if it's in the old (depricated) place (datadir) and read it from there # extra_args="" if test -r "$basedir/my.cnf" then extra_args="-e $basedir/my.cnf" else if test -r "$datadir/my.cnf" then extra_args="-e $datadir/my.cnf" fi fi
剖析设置文件中的参数
my_print_defaults的用法以下:
my_print_defaults --defaults-file=example.cnf client mysql
即读取设置文件中,client和mysql部份的参数设置,
细致在本剧本中,是读取mysqld,server,mysql_server,mysql.server四个部份的设置参数。
parse_server_arguments `$print_defaults $extra_args mysqld server mysql_server mysql.server`
设置pid file的途径
-z string 推断字符串是不是为空
假如--pid-file没有在读取到的设置文件中设置或许剧本刚开始的mysqld_pid_file_path参数没有设置,
则pid file默许设置在datadir下,以主机名.pid定名。
假如该参数设置了,还需要进一步推断
假如该参数中带有斜杠,则代表给定的值带有途径,可直接运用。
假如该参数中没带途径,则代表给定的值只是pid的文件名,可将其设在datadir下。
# # Set pid file if not given # if test -z "$mysqld_pid_file_path" then mysqld_pid_file_path=$datadir/`hostname`.pid else case "$mysqld_pid_file_path" in /* ) ;; * ) mysqld_pid_file_path="$datadir/$mysqld_pid_file_path" ;; esac fi
效劳剧本start选项
起首,切换到$basedir中
其次,推断$basedir/bin中的mysqld_safe是不是是可实行文件,假如是,则启动mysqld实例,假如不是,则报错退出。
那末,启动流程又是怎样完成的呢?
起首,实行$bindir/mysqld_safe --datadir="$datadir" --pid-file="$mysqld_pid_file_path" $other_args >/dev/null 2>&1 &敕令,启动mysqld实例。
注重到没有,mysqld_safe实际上是在basedir中实行的,包含mysql初始化剧本mysql_install_db,也发起在basedir中实行,细致可参考:
剖析MariaDB初始化剧本mysql_install_db
然后经由历程wait_for_pid函数举行推断,细致可见下文关于wait_for_pid函数的剖析
推断终了后,
检察$lockdir目次是不是可写,可写的话,则在目次上建立一个文件。
case "$mode" in 'start') # Start daemon # Safeguard (relative paths, core dumps..) cd $basedir echo $echo_n "Starting MySQL" if test -x $bindir/mysqld_safe then # Give extra arguments to mysqld with the my.cnf file. This script # may be overwritten at next upgrade. $bindir/mysqld_safe --datadir="$datadir" --pid-file="$mysqld_pid_file_path" $other_args >/dev/null 2>&1 & wait_for_pid created "$!" "$mysqld_pid_file_path"; return_value=$? # Make lock for RedHat / SuSE if test -w "$lockdir" then touch "$lock_file_path" fi exit $return_value else log_failure_msg "Couldn't find MySQL server ($bindir/mysqld_safe)" fi ;;
wait_for_pid函数
在应用mysqld_safe启动mysql实例后,会挪用该参数
wait_for_pid created "$!" "$mysqld_pid_file_path"; return_value=$?
个中$!在shell中用于猎取末了运转的背景Process的PID,细致在本例中,是mysqld_safe历程的pid。
由于第一个参数是created,所以会实行test -s "$pid_file_path" && i='' && break敕令。
-s file 假如文件的长度不为零,则为真
该敕令的意义是假如pid文件存在,则将变量i设置为空,并退出while轮回。
然后实行以下推断,
if test -z "$i" ; then log_success_msg return 0 else log_failure_msg return 1 fi
假如$i为空,则打印胜利日记,并退出剧本,很显然,在pid文件存在的状况下,会将变量i设置为空。
再来看看pid文件不存在的状况
起首,会推断$pid是不是不为空(即if test -n "$pid")
假如不为空,则代表在实行完mysqld_safe后,已捕获到了该历程的pid。
在这类状况下,进一步经由历程kill -0 "$pid"确认该历程是不是存在。
kill -0就是不发送任何信号,然则体系会举行毛病搜检,所以常经常使用来搜检一个历程是不是存在,当历程不存在时, kill -0 pid会返回毛病
假如该历程存在,则不实行任何操纵,直接跳到以下操纵
echo $echo_n ".$echo_c" i=`expr $i + 1` sleep 1
将变量i加1,并sleep 1s。
然后,继承while轮回,之所以如许做,是考虑到mysqld_safe已实行,然则mysqld实例还在启动历程当中,还没建立好pid文件。
一直到$1到达$service_startup_timeout定义的时长。
假如在while轮回的历程当中,经由历程kill -0 "$pid"推断到历程已不存在了,
则会再推断一次,假如此次推断的效果依旧是pid file不存在,且历程不存在,则会实行
log_failure_msg "The server quit without updating PID file ($pid_file_path)."
这就是赫赫有名的“The server quit without updating PID file”的由来。
wait_for_pid () { verb="$1" # created | removed pid="$2" # process ID of the program operating on the pid-file pid_file_path="$3" # path to the PID file. i=0 avoid_race_condition="by checking again" while test $i -ne $service_startup_timeout ; do case "$verb" in 'created') # wait for a PID-file to pop into existence. test -s "$pid_file_path" && i='' && break ;; 'removed') # wait for this PID-file to disappear test ! -s "$pid_file_path" && i='' && break ;; *) echo "wait_for_pid () usage: wait_for_pid created|removed pid pid_file_path" exit 1 ;; esac # if server isn't running, then pid-file will never be updated if test -n "$pid"; then if kill -0 "$pid" 2>/dev/null; then : # the server still runs else # The server may have exited between the last pid-file check and now. if test -n "$avoid_race_condition"; then avoid_race_condition="" continue # Check again. fi # there's nothing that will affect the file. log_failure_msg "The server quit without updating PID file ($pid_file_path)." return 1 # not waiting any more. fi fi echo $echo_n ".$echo_c" i=`expr $i + 1` sleep 1 done if test -z "$i" ; then log_success_msg return 0 else log_failure_msg return 1 fi }
效劳剧本stop选项
起首,推断pid文件的长度是不是不为零。
-s file 假如文件的长度不为零,则为真
此时,会经由历程pid文件猎取mysqld历程的pid,注重,不是mysqld_safe历程的pid
然后,推断mysqld历程是不是在一般运转,
假如是,则经由历程kill $mysqld_pid的体式格局来封闭mysqld历程
杀死历程最平安的要领是纯真运用kill敕令,不加修饰符,不带标志。
规范的kill敕令一般会住手有题目标历程,并把历程的资本释放给体系。但是,假如历程启动了子历程,只杀死父历程,子历程仍在运转,因而仍斲丧资本。为了防备这些所谓的“僵尸历程”,应确保在杀死父历程之前,先杀死其一切的子历程。
然后,挪用wait_for_pid函数举行推断,实在,wait_for_pid函数中设置avoid_race_condition变量的目标是为了stop选项,确切有能够涌现,mysqld是在搜检pid file以后,搜检历程是不是存活之前退出的。
假如mysqld历程没有一般运转,在会打印“MySQL server process #$mysqld_pid is not running!”信息,并删除pid文件。
假如在实行stop的时刻,推断pid文件的长度为0,则会打印"MySQL server PID file could not be found!"信息。
所以,在pid文件不存在的状况下,经由历程效劳剧本实行stop选项并不会封闭mysqld历程,这个时刻,便可经由历程kill $mysqld_pid的体式格局来封闭mysqld历程。
'stop') # Stop daemon. We use a signal here to avoid having to know the # root password. if test -s "$mysqld_pid_file_path" then mysqld_pid=`cat "$mysqld_pid_file_path"` if (kill -0 $mysqld_pid 2>/dev/null) then echo $echo_n "Shutting down MySQL" kill $mysqld_pid # mysqld should remove the pid file when it exits, so wait for it. wait_for_pid removed "$mysqld_pid" "$mysqld_pid_file_path"; return_value=$? else log_failure_msg "MySQL server process #$mysqld_pid is not running!" rm "$mysqld_pid_file_path" fi # Delete lock for RedHat / SuSE if test -f "$lock_file_path" then rm -f "$lock_file_path" fi exit $return_value else log_failure_msg "MySQL server PID file could not be found!" fi ;;
效劳剧本restart选项
起首,先实行stop操纵,假如stop操纵胜利的话,则继承实行start操纵。
假如stop操纵失利的话,则会输出"Failed to stop running server, so refusing to try to start."信息,并退出剧本。
'restart') # Stop the service and regardless of whether it was # running or not, start it again. if $0 stop $other_args; then $0 start $other_args else log_failure_msg "Failed to stop running server, so refusing to try to start." exit 1 fi ;;
效劳剧本reload选项
起首,推断pid文件的长度是不是为0,假如不为0,则将该文件中的值设置为mysqld_pid变量的值。
然后对该历程实行kill -HUP操纵。
kill -HUP pid
pid 是历程标识。假如想要变动设置而不需住手并从新启动效劳,请运用该敕令。在对设置文件作必要的变动后,发出该敕令以动态更新效劳设置。
依据商定,当您发送一个挂起信号(信号 1 或 HUP)时,大多数效劳器历程(一切经常使用的历程)都邑举行复位操纵并从新加载它们的设置文件。
假如pid文件的长度为0,则输出"MySQL PID file could not be found!"。
'reload'|'force-reload') if test -s "$mysqld_pid_file_path" ; then read mysqld_pid < "$mysqld_pid_file_path" kill -HUP $mysqld_pid && log_success_msg "Reloading service MySQL" touch "$mysqld_pid_file_path" else log_failure_msg "MySQL PID file could not be found!" exit 1 fi ;;
效劳剧本status选项
起首,推断pid文件长度是不是为0,假如不是,则读取该文件中的值,并推断pid对应的历程是不是运转一般,
假如运转一般,则输出"MySQL running"
假如不一般,则输出"MySQL is not running, but PID file exists"
假如pid文件的长度为0,则试图经由历程mysqld的启动敕令来猎取其pid,
这个时刻,能够存在一个mysqld顺序启动了多个实例,这会致使pid_count=`echo $mysqld_pid | wc -w`大于1。
这个时刻,会输出"Multiple MySQL running but PID file could not be found"信息,并退出剧本。
假如mysqld_pid为空,则会继承推断"$lock_file_path"是不是存在,假如存在,
则会输出"MySQL is not running, but lock file ($lock_file_path) exists"信息。
假如"$lock_file_path"不存在,则会输出"MySQL is not running"信息。
假如mysqld_pid即是1,则会输出"MySQL is running but PID file could not be found"信息。
'status') # First, check to see if pid file exists if test -s "$mysqld_pid_file_path" ; then read mysqld_pid < "$mysqld_pid_file_path" if kill -0 $mysqld_pid 2>/dev/null ; then log_success_msg "MySQL running ($mysqld_pid)" exit 0 else log_failure_msg "MySQL is not running, but PID file exists" exit 1 fi else # Try to find appropriate mysqld process mysqld_pid=`pidof $libexecdir/mysqld` # test if multiple pids exist pid_count=`echo $mysqld_pid | wc -w` if test $pid_count -gt 1 ; then log_failure_msg "Multiple MySQL running but PID file could not be found ($mysqld_pid)" exit 5 elif test -z $mysqld_pid ; then if test -f "$lock_file_path" ; then log_failure_msg "MySQL is not running, but lock file ($lock_file_path) exists" exit 2 fi log_failure_msg "MySQL is not running" exit 3 else log_failure_msg "MySQL is running but PID file could not be found" exit 4 fi fi ;;
效劳剧本别的选项
假如剧本的第一个参数不是上述几个选项,则会输出Usage信息。
*) # usage basename=`basename "$0"` echo "Usage: $basename {start|stop|restart|reload|force-reload|status} [ MySQL server options ]" exit 1 ;;
至此,mysql的效劳剧本剖析终了~
总结
在经由历程效劳剧本启动mysql的历程当中,报“The server quit without updating PID file”毛病,有两个前提
起首,pid文件不存在
其次,经由历程kill -0 $pid搜检到历程并不存在
这个时刻,只能经由历程mysql数据库的毛病日记来定位。
效劳剧本假如不做任何调解的话,默许的basedir是/usr/local/mysql,datadir是/usr/local/mysql/data
假如本身的mysql效劳均不是默许途径,
则需要在该剧本中显式设置
经测试,需设置以下几处:
1. 设置basedir和增加conf变量
个中,conf指的是mysqld的设置文件,发起设置文件中显式指定basedir和datadir的值。
在这里,datadir可不设置,由于datadir可经由历程设置文件来猎取。
然则basedir必需要指定,由于要起首依据basedir来推断my_print_deefauts敕令
basedir=/usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64 datadir= conf=/usr/local/mysql-advanced-5.6.23-linux-glibc2.5-x86_64/my_3308.cnf
2. 第256行,增加extra_args=" -c $conf"
extra_args=" -e $basedir/my.cnf.bak" if test -r "$basedir/my.cnf" then extra_args="-e $basedir/my.cnf" else if test -r "$datadir/my.cnf" then extra_args="-e $datadir/my.cnf" fi fi extra_args=" -c $conf"
3. 修正285行mysqld_safe的启动参数
将
$bindir/mysqld_safe --datadir="$datadir" --pid-file="$mysqld_pid_file_path" $other_args >/dev/null 2>&1 &
修正为,
$bindir/mysqld_safe --defaults-file="$conf" --datadir="$datadir" --pid-file="$mysqld_pid_file_path" $other_args >/dev/null 2>&1 &
重如果增加了--defaults-file选项
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