发布于 2017-10-14 02:56:47 | 172 次阅读 | 评论: 0 | 来源: 网友投递
Mysql关系型数据库管理系统
MySQL是一个开放源码的小型关联式数据库管理系统，开发者为瑞典MySQL AB公司。MySQL被广泛地应用在Internet上的中小型网站中。由于其体积小、速度快、总体拥有成本低，尤其是开放源码这一特点，许多中小型网站为了降低网站总体拥有成本而选择了MySQL作为网站数据库。
MySQL无法启动的解决办法
MySQL无法启动
在停止mysql之后，执行了一些操作（如修改主机名），重新启动 mysql，发现起不来。
[root@www ~]$ service mysql start
Starting MySQL..^[[A.................................................................................................. ERROR! The server quit without updating PID file (/disk/mysql/www.pid).
[root@www ~]$ service mysql stop
ERROR! MySQL server PID file could not be found!
[root@www ~]$ service mysql stop
ERROR! MySQL server PID file could not be found!
[root@www ~]$ service mysql start
Starting MySQL..................
还是老样子，只好 Ctr+C 掉。
[root@www ~]$
实在是启动不了，看一下日志：/disk/mysql/www.err
120608 09:56:17 mysqld_safe Starting mysqld daemon with databases from /disk/mysql
120608 9:56:17 [Note] Plugin 'FEDERATED' is disabled.
120608 9:56:17 InnoDB: The InnoDB memory heap is disabled
120608 9:56:17 InnoDB: Mutexes and rw_locks use InnoDB's own implementation
120608 9:56:17 InnoDB: Compressed tables use zlib 1.2.3
120608 9:56:17 InnoDB: Using Linux native AIO
120608 9:56:17 InnoDB: Initializing buffer pool, size = 128.0M
120608 9:56:17 InnoDB: Completed initialization of buffer pool
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
120608 9:56:17 InnoDB: Retrying to lock the first data file
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.
InnoDB: Unable to lock ./ibdata1, error: 11
...
好像是原来的 mysqld 并没有停下来。
强制终止 mysqld
[root@www ~]$ ps -ef|grep mysql
root 4769 1 0 Jun06 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/disk/mysql --pid-file=/disk/mysql/localhost.pid
mysql 4874 4769 0 Jun06 ? 00:04:04 /usr/sbin/mysqld --basedir=/usr --datadir=/disk/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/disk/mysql/localhost.err --pid-file=/disk/mysql/localhost.pid --socket=/disk/mysql/mysql.sock
root 17947 1 0 09:56 pts/1 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/disk/mysql --pid-file=/disk/mysql/www.pid
mysql 18052 17947 0 09:56 pts/1 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/disk/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/disk/mysql/www.err --pid-file=/disk/mysql/www.pid --socket=/disk/mysql/mysql.sock
root 18099 17514 0 09:56 pts/1 00:00:00 grep mysql
[root@www ~]$ killall mysqld
[root@www ~]$ killall mysqld
[root@www ~]$ ps -ef|grep mysql
root 18116 17514 0 09:57 pts/1 00:00:00 grep mysql
[root@www ~]$
启动 mysqld ，现在执行多次启动命令都没有问题。
[root@www ~]$ service mysql start
Starting MySQL. SUCCESS!
[root@www ~]$
[root@www ~]$
[root@www ~]$
[root@www ~]$
[root@www ~]$ service mysql start
Starting MySQL SUCCESS!
[root@www ~]$
前面 www.err 文件中显示的 error: 11 到底是什么，看下：
[root@www ~]$ perror 11
OS error code 11: Resource temporarily unavailable
[root@www ~]$
[root@www ~]$
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