linux 下mysql的启动 、调试、排错

    the most simplest usage of mysqld_safe way is to just use '--defaults-file' to specify which "my.cnf" you want to use,just like:

1.1.2 mysqld_safe — MySQL Server Startup Script

mysqld_safe is the recommended way to start a mysqld server on Unix. mysqld_safe adds somesafety features such as restarting the server when an error occurs and loggingruntime information to an error log file. A description of error logging isgiven later in this section.

mysqld_safe triesto start an executable named mysqld. To override the default behavior andspecify explicitly the name of the server you want to run, specify a --mysqld or--mysqld-version option to mysqld_safe. You can also use --ledir to indicate thedirectory where mysqld_safe should look for the server.

 mysqld_safe readsall options from the [mysqld], [server], and [mysqld_safe] sections in optionfiles. For example, if you specify a [mysqld] section like this, mysqld_safe willfind and use the --log-error option:

[mysqld]

log-error=error.log

For backwardcompatibility, mysqld_safe also reads [safe_mysqld] sections, although youshould rename such sections to [mysqld_safe] in MySQL 5.5 installations.

--mysqld_safe 会帮助我们来监控mysqld 进程的状态,当mysqld 进程crash 之后,mysqld_safe会马上帮助我们重启mysqld 进程。但前提是我们必须通过mysqld_safe 来启动MySQLServer,这也是MySQL AB 强烈推荐的做法。

 

 

3. The server stopsaccepting new connections.

To prevent newactivity from being initiated during shutdown, the server stops accepting newclient connections by closing the handlers for the network interfaces to whichit normally listens for connections: the TCP/IP port, the Unix socket file, theWindows named pipe, and shared memory on Windows.

 

 

1.2  启动进程的参数

The MySQL servermaintains many system variables that indicate how it is configured. Each systemvariable has a default value. System variables can be set at server startupusing options on the command line or in an option file. Most of them can bechanged dynamically while the server is running by means of the SET statement,which enables you to modify operation of the server without having to stop andrestart it. You can refer to system variable values in expressions

 

在启动MySQL 时,我们可以手工的在命令后面指定相关的参数, 如上面ps 的命令显示的一样:

/usr/sbin/mysqld --basedir=/usr--datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql--log-error=/var/lib/mysql/rac2.err --pid-file=/var/lib/mysql/rac2.pid--socket=/var/lib/mysql/mysql.sock --port=3306

 

这里是我们的默认的一个参数值,我们可以通过如下命令来查看MySQL的默认参数的具体值:

(1)To see the values that a serverwill use based on its compiled-in defaults and any option files that it reads,use this command:

mysqld --verbose--help

(2)To see the values that a serverwill use based on its compiled-in defaults, ignoring the settings in any optionfiles, use this command:

mysqld --no-defaults --verbose --help

      

如果每次启动都手工的指定参数比较麻烦,我们可以把相关的参数配置到参数文件里,在MySQL启动时会读取这些文件,参数文件的位置:

 

On Unix, Linux and Mac OS X, MySQL programsread startup options from the following files, in the specified order (topitems are used first).

 图片 1

 

注意上表中参数文件的顺序,MySQL 会按照从上往下的顺序优先使用上面的参数文件,这个就类似与Oracle的SPFILE,PFILE和 init 文件的读取顺序一样。

 

~ represents the current user's home directory (the value of $HOME).

SYSCONFDIR representsthe directory specified with the SYSCONFDIR option to CMake when MySQL wasbuilt. By default, this is the etc directory located under the compiled-ininstallation directory.

 

MYSQL_HOME is anenvironment variable containing the path to the directory in which theserver-specific my.cnf file resides. If MYSQL_HOME is not set and you start theserver using the mysqld_safe program, mysqld_safe attempts to set MYSQL_HOME asfollows:

(1)Let BASEDIR and DATADIR representthe path names of the MySQL base directory and data directory, respectively.

(2)If there is a my.cnf file in DATADIRbut not in BASEDIR, mysqld_safe sets MYSQL_HOME to DATADIR.

(3)Otherwise, if MYSQL_HOME is not setand there is no my.cnf file in DATADIR, mysqld_safe sets MYSQL_HOME to BASEDIR.

 

In MySQL 5.5,use of DATADIR as the location for my.cnf is deprecated.

       --在MySQL 5.5中,my.cnf 文件已经不放在DATADIR目录下。

 

Typically, DATADIRis /usr/local/mysql/data for a binary installation or /usr/local/var for asource installation. Note that this is the data directory location that wasspecified at configuration time, not the one specified with the --datadir optionwhen mysqld starts. Use of --datadir at runtime has no effect on where theserver looks for option files, because it looks for them before processing anyoptions.

 

我的测试版本:

mysql> selectversion(),current_user();

+------------+----------------+

| version()  | current_user() |

+------------+----------------+

| 5.5.15-log |root@localhost |

+------------+----------------+

1 row in set(0.02 sec)

 

里并没有my.cnf 文件,只在/usr/share/mysql目录下面有几个类似的文件:

 

[root@rac2 mysql]# pwd

/usr/share/mysql

[root@rac2 mysql]# ls my*

my-huge.cnf             my-small.cnf         mysql_system_tables_data.sql

my-innodb-heavy-4G.cnf  mysqld_multi.server  mysql_system_tables.sql

my-large.cnf            mysql-log-rotate     mysql_test_data_timezone.sql

my-medium.cnf           mysql.server

 

我们copy 一个到/etc 目录下:

[root@rac2 mysql]# cp /usr/share/mysql/my-medium.cnf /etc/my.cnf

 

从上面了解到,MySQL 在启动时会先使用/etc/my.cnf的配置文件,如果没有在使用其他的文件,所以我们修改该配置文件里的相关参数即可。

 


1.2  启动进程的参数

The MySQL servermaintains many system variables that indicate how it is configured. Each systemvariable has a default value. System variables can be set at server startupusing options on the command line or in an option file. Most of them can bechanged dynamically while the server is running by means of the SET statement,which enables you to modify operation of the server without having to stop andrestart it. You can refer to system variable values in expressions

 

在启动MySQL 时,我们可以手工的在命令后面指定相关的参数, 如上面ps 的命令显示的一样:

/usr/sbin/mysqld --basedir=/usr--datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql--log-error=/var/lib/mysql/rac2.err --pid-file=/var/lib/mysql/rac2.pid--socket=/var/lib/mysql/mysql.sock --port=3306

 

这里是我们的默认的一个参数值,我们可以通过如下命令来查看MySQL的默认参数的具体值:

(1)To see the values that a serverwill use based on its compiled-in defaults and any option files that it reads,use this command:

mysqld --verbose--help

(2)To see the values that a serverwill use based on its compiled-in defaults, ignoring the settings in any optionfiles, use this command:

mysqld --no-defaults --verbose --help

      

如果每次启动都手工的指定参数比较麻烦,我们可以把相关的参数配置到参数文件里,在MySQL启动时会读取这些文件,参数文件的位置:

 

On Unix, Linux and Mac OS X, MySQL programsread startup options from the following files, in the specified order (topitems are used first).

 图片 2

 

注意上表中参数文件的顺序,MySQL 会按照从上往下的顺序优先使用上面的参数文件,这个就类似与Oracle的SPFILE,PFILE和 init 文件的读取顺序一样。

 

~ represents the current user's home directory (the value of $HOME).

SYSCONFDIR representsthe directory specified with the SYSCONFDIR option to CMake when MySQL wasbuilt. By default, this is the etc directory located under the compiled-ininstallation directory.

 

MYSQL_HOME is anenvironment variable containing the path to the directory in which theserver-specific my.cnf file resides. If MYSQL_HOME is not set and you start theserver using the mysqld_safe program, mysqld_safe attempts to set MYSQL_HOME asfollows:

(1)Let BASEDIR and DATADIR representthe path names of the MySQL base directory and data directory, respectively.

(2)If there is a my.cnf file in DATADIRbut not in BASEDIR, mysqld_safe sets MYSQL_HOME to DATADIR.

(3)Otherwise, if MYSQL_HOME is not setand there is no my.cnf file in DATADIR, mysqld_safe sets MYSQL_HOME to BASEDIR.

 

In MySQL 5.5,use of DATADIR as the location for my.cnf is deprecated.

       --在MySQL 5.5中,my.cnf 文件已经不放在DATADIR目录下。

 

Typically, DATADIRis /usr/local/mysql/data for a binary installation or /usr/local/var for asource installation. Note that this is the data directory location that wasspecified at configuration time, not the one specified with the --datadir optionwhen mysqld starts. Use of --datadir at runtime has no effect on where theserver looks for option files, because it looks for them before processing anyoptions.

 

我的测试版本:

mysql> selectversion(),current_user();

+------------+----------------+

| version()  | current_user() |

+------------+----------------+

| 5.5.15-log |root@localhost |

+------------+----------------+

1 row in set(0.02 sec)

 

里并没有my.cnf 文件,只在/usr/share/mysql目录下面有几个类似的文件:

 

[root@rac2 mysql]# pwd

/usr/share/mysql

[root@rac2 mysql]# ls my*

my-huge.cnf             my-small.cnf         mysql_system_tables_data.sql

my-innodb-heavy-4G.cnf  mysqld_multi.server  mysql_system_tables.sql

my-large.cnf            mysql-log-rotate     mysql_test_data_timezone.sql

my-medium.cnf           mysql.server

 

我们copy 一个到/etc 目录下:

[root@rac2 mysql]# cp /usr/share/mysql/my-medium.cnf /etc/my.cnf

 

从上面了解到,MySQL 在启动时会先使用/etc/my.cnf的配置文件,如果没有在使用其他的文件,所以我们修改该配置文件里的相关参数即可。

 

 1 [root@zlm3 07:54:10 /usr/local/mysql/bin]
 2 #pkill mysqld
 3 
 4 [root@zlm3 07:54:40 /usr/local/mysql/bin]
 5 #ps aux|grep mysqld
 6 root      6302  0.0  0.0 112640   960 pts/0    R+   07:54   0:00 grep --color=auto mysqld
 7 
 8 [root@zlm3 07:54:51 /usr/local/mysql/bin]
 9 #mysqld_safe --defaults-file=/data/mysql/mysql3306/my.cnf &
10 [1] 6307
11 
12 [root@zlm3 07:55:21 /usr/local/mysql/bin]
13 #2018-06-04T05:55:21.758814Z mysqld_safe Logging to '/data/mysql/mysql3306/data/error.log'.
14 2018-06-04T05:55:21.786306Z mysqld_safe Starting mysqld daemon with databases from /data/mysql/mysql3306/data
15 ^C
16 
17 [root@zlm3 07:55:35 /usr/local/mysql/bin]
18 #ps aux|grep mysqld
19 root      6307  0.1  0.1 113252  1628 pts/0    S    07:55   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --defaults-file=/data/mysql/mysql3306/my.cnf
20 mysql     7328  1.0 17.4 1069424 177592 pts/0  Sl   07:55   0:00 /usr/local/mysql/bin/mysqld --defaults-file=/data/mysql/mysql3306/my.cnf --basedir=/usr/local/mysql --datadir=/data/mysql/mysql3306/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=error.log --open-files-limit=65535 --pid-file=mysql.pid --socket=/tmp/mysql3306.sock --port=3306
21 root      7361  0.0  0.0 112640   960 pts/0    R+   07:55   0:00 grep --color=auto mysqld
22 
23 [root@zlm3 07:55:44 /usr/local/mysql/bin]
24 #

1.1.2 mysqld_safe — MySQL Server Startup Script

mysqld_safe is the recommended way to start a mysqld server on Unix. mysqld_safe adds somesafety features such as restarting the server when an error occurs and loggingruntime information to an error log file. A description of error logging isgiven later in this section.

mysqld_safe triesto start an executable named mysqld. To override the default behavior andspecify explicitly the name of the server you want to run, specify a --mysqld or--mysqld-version option to mysqld_safe. You can also use --ledir to indicate thedirectory where mysqld_safe should look for the server.

 mysqld_safe readsall options from the [mysqld], [server], and [mysqld_safe] sections in optionfiles. For example, if you specify a [mysqld] section like this, mysqld_safe willfind and use the --log-error option:

[mysqld]

log-error=error.log

For backwardcompatibility, mysqld_safe also reads [safe_mysqld] sections, although youshould rename such sections to [mysqld_safe] in MySQL 5.5 installations.

--mysqld_safe 会帮助我们来监控mysqld 进程的状态,当mysqld 进程crash 之后,mysqld_safe会马上帮助我们重启mysqld 进程。但前提是我们必须通过mysqld_safe 来启动MySQLServer,这也是MySQL AB 强烈推荐的做法。

 

 

3.2 手工启动和关闭MySQL 示例

[root@rac2 /]#/usr/share/mysql/mysql.server stop

Shutting down MySQL.                                       [  OK  ]

[root@rac2 /]#/usr/share/mysql/mysql.server start

Starting MySQL....                                         [  OK  ]

[root@rac2 /]# service mysql stop

Shutting down MySQL.                                       [  OK  ]

[root@rac2 /]# service mysql start

Starting MySQL......                                       [ OK  ]

 

mysql.server stop stops the server by sending a signal to it. You can also stop the servermanually by executing mysqladmin shutdown.

 

[root@rac2 run]# mysqladmin shutdown

[root@rac2 run]# ps -ef|grep mysql 

root    30997  3596  0 14:51 pts/1    00:00:00 grep mysql

 

Mysqladmin 不能用来启动mysql。只能用来关闭。没有对应的启动语法。这个具体可以通过如下命令查看:

[root@rac2 run]# mysqladmin --help

 

另一个需要注意的问题,/var/lib/mysql/mysql.sock 文件仅在mysql 进程启动时才有,一旦mysql关闭,改文件也就自动清除。

 

[root@rac2 run]# ls /var/lib/mysql/mysql.sock

ls: /var/lib/mysql/mysql.sock: No such fileor directory

[root@rac2 run]# service mysql start

Starting MySQL.....                                        [  OK  ]

[root@rac2 run]# ls/var/lib/mysql/mysql.sock

/var/lib/mysql/mysql.sock

 

 

 

 

转载自 : http://blog.csdn.net/tianlesoftware

 

三.相关示例

    today,one buddy in IMG wechat group 2 asked "why i've installed the MySQL 5.7 on linux server,but there's no mysqld_safe command at all?"so,here i'd like to post this article to say something about it.first of all,let's see the command parameter and usage:

1.1  MySQL 进程

可以用ps 命令查看进程:

[root@rac2 ~]# ps -ef|grep mysql

root     2161     1  0 09:38 ?        00:00:00 /bin/sh /usr/bin/mysqld_safe--datadir=/var/lib/mysql --pid-file=/var/lib/mysql/rac2.pid

mysql    2418  2161  0 09:38 ?        00:00:00 /usr/sbin/mysqld--basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin--user=mysql --log-error=/var/lib/mysql/rac2.err--pid-file=/var/lib/mysql/rac2.pid --socket=/var/lib/mysql/mysql.sock--port=3306

root     3628  3596  0 09:57 pts/1    00:00:00 grep mysql

 

Note

三.相关示例

4.3.2 mysqld_safe — MySQL Server Startup Script

mysqld_safe is the recommended way to start a mysqld server on Unix. mysqld_safe adds some safety features such as restarting the server when an error occurs and logging runtime information to an error log. A description of error logging is given later in this section.

 来源: https://dev.mysql.com/doc/refman/8.0/en/mysqld-safe.html 


 

summary:

    another buddy in zst techique wechat group said that it will be messy in troubleshooting while using mysqld_safe to startup mysqld,'cause in some case,the mysqld_safe may lead to the ceaseless restarting of mysqld.furthermore,it may destroy the evidences and logs which can be diagnosted by DBAs.anyhow,in my opinion it depends:

  • if the bussines continuity is the first thing you need to consider,i recommend to use mysqld_safe method.
  • if your monitor system is strong enough or the application on the MySQL server is not so important such as enterprise management system,BBS system,i recommend to use mysqld method.

4. The server terminatescurrent activity.

For each threadassociated with a client connection, the server breaks the connection to theclient and marks the thread as killed. Threads die when they notice that theyare so marked. Threads for idle connections die quickly. Threads that currentlyare processing statements check their state periodically and take longer todie. For additional information about thread termination, see Section 12.7.6.4,“KILL Syntax”, in particular for the instructions about killed REPAIR TABLE or OPTIMIZETABLE operations on MyISAM tables.

For threads thathave an open transaction, the transaction is rolled back. Note that if a threadis updating a nontransactional table, an operation such as a multiple-row UPDATEor INSERT may leave the table partially updated because the operation canterminate before completion. If the server is a master replication server, ittreats threads associated with currently connected slaves like other clientthreads. That is, each one is marked as killed and exits when it next checksits state.

If the server isa slave replication server, it stops the the I/O and SQL threads, if they areactive, before marking client threads as killed. The SQL thread is permitted tofinish its current statement (to avoid causing replication problems), and thenstops. If the SQL thread was in the middle of a transaction at this point, thetransaction is rolled back.

If the slave isupdating a non-transactional table when it is forcibly killed, the slave's datamay become inconsistent with the master.

 

  1. The server shuts downor closes storage engines.

At this stage,the server flushes the table cache and closes all open tables. Each storageengine performs any actions necessary for tables that it manages. For example, MyISAMflushes any pending index writes for a table. InnoDB flushes its buffer pool todisk (unless innodb_fast_shutdown is 2), writes the current LSN to the tablespace,and terminates its own internal threads.

 

  1. The server exits.

 

 1 [root@zlm3 07:55:44 /usr/local/mysql/bin]
 2 #kill -9 7328
 3 
 4 [root@zlm3 07:57:15 /usr/local/mysql/bin]
 5 #/usr/local/mysql/bin/mysqld_safe: line 198:  7328 Killed                  nohup /usr/local/mysql/bin/mysqld --defaults-file=/data/mysql/mysql3306/my.cnf --basedir=/usr/local/mysql --datadir=/data/mysql/mysql3306/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=error.log --open-files-limit=65535 --pid-file=mysql.pid --socket=/tmp/mysql3306.sock --port=3306 < /dev/null > /dev/null 2>&1
 6 2018-06-04T05:57:15.076914Z mysqld_safe Number of processes running now: 0
 7 2018-06-04T05:57:15.083092Z mysqld_safe mysqld restarted
 8 ^C
 9 
10 [root@zlm3 07:57:20 /usr/local/mysql/bin]
11 #ps aux|grep mysqld
12 root      6307  0.0  0.1 113256  1676 pts/0    S    07:55   0:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --defaults-file=/data/mysql/mysql3306/my.cnf
13 mysql     7385  2.4 17.7 1081288 180624 pts/0  Sl   07:57   0:00 /usr/local/mysql/bin/mysqld --defaults-file=/data/mysql/mysql3306/my.cnf --basedir=/usr/local/mysql --datadir=/data/mysql/mysql3306/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=error.log --open-files-limit=65535 --pid-file=mysql.pid --socket=/tmp/mysql3306.sock --port=3306
14 root      7419  0.0  0.0 112640   960 pts/0    R+   07:57   0:00 grep --color=auto mysqld
15 
16 [root@zlm3 07:57:24 /usr/local/mysql/bin]
17 #pkill mysqld
18 
19 [root@zlm3 07:57:37 /usr/local/mysql/bin]
20 #2018-06-04T05:57:38.957789Z mysqld_safe mysqld from pid file /data/mysql/mysql3306/data/mysql.pid ended
21 ^C
22 [1]+  Done                    mysqld_safe --defaults-file=/data/mysql/mysql3306/my.cnf
23 
24 [root@zlm3 07:57:48 /usr/local/mysql/bin]
25 #ps aux|grep mysqld
26 root      7439  0.0  0.0 112640   956 pts/0    R+   07:57   0:00 grep --color=auto mysqld
27 
28 [root@zlm3 07:57:55 /usr/local/mysql/bin]
29 #

3.1 部署MySQL自启动

To start andstop MySQL automatically on your server, you need to add start and stopcommands to the appropriate places in your /etc/rc* files.

--如果配置MySQL的自动启用和关闭,需要讲相关命令添加到/etc/rc*目录里。

If you use theLinux server RPM package (MySQL-server-VERSION.rpm), or a native Linux packageinstallation, the mysql.server script may be installed in the /etc/init.d directorywith the name mysql. See Section 2.5.1, “Installing MySQL from RPM Packages onLinux”, for more information on the Linux RPM packages.Some vendors provide RPMpackages that install a startup script under a different name such as mysqld.

--如果是使用RPM包来安装的,已经部署到/etc/init.d/mysql了脚本,不需要其他配置。

If you installMySQL from a source distribution or using a binary distribution format thatdoes not install mysql.server automatically, you can install it manually. Thescript can be found in the support-files directory under the MySQL installationdirectory or in a MySQL source tree.

 

To install mysql.servermanually, copy it to the /etc/init.d directory with the name mysql, and thenmake it executable. Do this by changing location into the appropriate directorywhere mysql.server is located and executing these commands:

       --如果手工的部署启动启动脚本,执行如下2个命令:

shell> cp mysql.server /etc/init.d/mysql

shell> chmod +x /etc/init.d/mysql

 

Note:

Older Red Hatsystems use the /etc/rc.d/init.d directory rather than /etc/init.d. Adjust thepreceding commands accordingly.

--老版本的Redhat 使用/etc/rc.d/init.d 代替/etc/init.d,所以需要创建一个link。

Alternatively,first create /etc/init.d as a symbolic link that points to /etc/rc.d/init.d:

shell> cd /etc

shell> ln -s rc.d/init.d .

 

After installingthe script, the commands needed to activate it to run at system startup dependon your operating system.

       --脚本安装完之后,需要激活自启动。

 

On Linux, you can use chkconfig:

shell> chkconfig --add mysql

On some Linux systems, the followingcommand also seems to be necessary to fully enable the mysql script:

shell> chkconfig --level 345 mysql on

 

 

    here we can see,there're two processes running,one is mysqld_safe,another one is the mysqld.even if you use "kill -9 7328" to stop the mysqld process,but subsequently you'll find that the mysqld will startup again soon,unless you kill mysqld process by using "pkill mysqld" as below:

3.1 部署MySQL自启动

To start andstop MySQL automatically on your server, you need to add start and stopcommands to the appropriate places in your /etc/rc* files.

--如果配置MySQL的自动启用和关闭,需要讲相关命令添加到/etc/rc*目录里。

If you use theLinux server RPM package (MySQL-server-VERSION.rpm), or a native Linux packageinstallation, the mysql.server script may be installed in the /etc/init.d directorywith the name mysql. See Section 2.5.1, “Installing MySQL from RPM Packages onLinux”, for more information on the Linux RPM packages.Some vendors provide RPMpackages that install a startup script under a different name such as mysqld.

--如果是使用RPM包来安装的,已经部署到/etc/init.d/mysql了脚本,不需要其他配置。

If you installMySQL from a source distribution or using a binary distribution format thatdoes not install mysql.server automatically, you can install it manually. Thescript can be found in the support-files directory under the MySQL installationdirectory or in a MySQL source tree.

 

To install mysql.servermanually, copy it to the /etc/init.d directory with the name mysql, and thenmake it executable. Do this by changing location into the appropriate directorywhere mysql.server is located and executing these commands:

       --如果手工的部署启动启动脚本,执行如下2个命令:

shell> cp mysql.server /etc/init.d/mysql

shell> chmod +x /etc/init.d/mysql

 

Note:

Older Red Hatsystems use the /etc/rc.d/init.d directory rather than /etc/init.d. Adjust thepreceding commands accordingly.

--老版本的Redhat 使用/etc/rc.d/init.d 代替/etc/init.d,所以需要创建一个link。

Alternatively,first create /etc/init.d as a symbolic link that points to /etc/rc.d/init.d:

shell> cd /etc

shell> ln -s rc.d/init.d .

 

After installingthe script, the commands needed to activate it to run at system startup dependon your operating system.

       --脚本安装完之后,需要激活自启动。

 

On Linux, you can use chkconfig:

shell> chkconfig --add mysql

On some Linux systems, the followingcommand also seems to be necessary to fully enable the mysql script:

shell> chkconfig --level 345 mysql on

 

 


一.启动

 

4. The server terminatescurrent activity.

For each threadassociated with a client connection, the server breaks the connection to theclient and marks the thread as killed. Threads die when they notice that theyare so marked. Threads for idle connections die quickly. Threads that currentlyare processing statements check their state periodically and take longer todie. For additional information about thread termination, see Section 12.7.6.4,“KILL Syntax”, in particular for the instructions about killed REPAIR TABLE or OPTIMIZETABLE operations on MyISAM tables.

For threads thathave an open transaction, the transaction is rolled back. Note that if a threadis updating a nontransactional table, an operation such as a multiple-row UPDATEor INSERT may leave the table partially updated because the operation canterminate before completion. If the server is a master replication server, ittreats threads associated with currently connected slaves like other clientthreads. That is, each one is marked as killed and exits when it next checksits state.

If the server isa slave replication server, it stops the the I/O and SQL threads, if they areactive, before marking client threads as killed. The SQL thread is permitted tofinish its current statement (to avoid causing replication problems), and thenstops. If the SQL thread was in the middle of a transaction at this point, thetransaction is rolled back.

If the slave isupdating a non-transactional table when it is forcibly killed, the slave's datamay become inconsistent with the master.

 

  1. The server shuts downor closes storage engines.

At this stage,the server flushes the table cache and closes all open tables. Each storageengine performs any actions necessary for tables that it manages. For example, MyISAMflushes any pending index writes for a table. InnoDB flushes its buffer pool todisk (unless innodb_fast_shutdown is 2), writes the current LSN to the tablespace,and terminates its own internal threads.

 

  1. The server exits.

 

    therefore,if you want the mysqld_safe feature,i rather recommend you to install MySQL server with binary distribution instead of rpm distribution.

/var/lib/mysql/mysql.sock下 MySQL 启动与关闭 说明

 

来源: https://dev.mysql.com/doc/refman/8.0/en/mysqld-safe.html 

1. The shutdown processis initiated.

This can occurinitiated several ways. For example, a user with the SHUTDOWN privilege canexecute a mysqladmin shutdown command. mysqladmin can be used on any platformsupported by MySQL. Other operating system-specific shutdown initiation methodsare possible as well: The server shuts down on Unix when it receives a SIGTERM signal.A server running as a service on Windows shuts down when the services managertells it to.

 

 

2.1 官网对shutdown的说明

The server shutdown process takes place asfollows:

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