Mysql误删了localhost.localdomain.pid文件

单位上周末施工，测试服务器断电两天，今天用到了数据库，启动数据库的时候，出现了很奇怪的问题

 

无法启动mysql，后来上网找了一下解决方法，无非就是以下几种

1. 注释/etc/my.cnf里的skip-federated注释掉即#skip-federated；

2. my.cnf文件配置过高，重新定义其中的参数（根据服务器情况定义）；

3. 杀掉mysql_safe和mysqld进程，然后再重启；

4. 当前日志文件过大，超出了my.cnf中定义的大小（默认为64M），删除日志文件再重启；

但是在主机中：

1．注释中无skip-federated这个选项

2．My.cnf是自己优化过的，断电之前正常使用，不是这个的问题

3．Ps –ef | grep mysql  根本就没有mysql的僵尸进程

4．没有这个问题

基本上网上的所有方式都试过了，都无法解决问题，然后我就打开了error.log，发现了 有些奇怪的地方 vi /var/lib/mysql/log/error.log

2014-06-10 11:52:46 15921 [Note] InnoDB: Database was not shutdown normally!

2014-06-10 11:52:46 15921 [Note] InnoDB: Starting crash recovery.

2014-06-10 11:52:46 15921 [Note] InnoDB: Reading tablespace information from the .ibd files... 2014-06-10 11:52:46 15921 [ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace raildb/base_company_fullname uses space ID: 4 at filepath: ./raildb/base_company_fullname.ibd. Cannot open tablespace mysql/slave_master_info which uses space ID: 4 at filepath: ./mysql/slave_master_info.ibd

2014-06-10 11:52:46 7ff29246d720  InnoDB: Operating system error number 2 in a file operation. InnoDB: The error means the system cannot find the path specified.

InnoDB: If you are installing InnoDB, remember that you must create

InnoDB: directories yourself, InnoDB does not create them.

InnoDB: Error: could not open single-table tablespace file ./mysql/slave_master_info.ibd

InnoDB: We do not continue the crash recovery, because the table may become

InnoDB: corrupt if we cannot apply the log records in the InnoDB log to it.

InnoDB: To fix the problem and start mysqld:

InnoDB: 1) If there is a permission problem in the file and mysqld cannot

InnoDB: open the file, you should modify the permissions.

InnoDB: 2) If the table is not needed, or you can restore it from a backup,

InnoDB: then you can remove the .ibd file, and

InnoDB will do a normal

InnoDB: crash recovery and ignore that table.

InnoDB: 3) If the file system or the disk is broken, and you cannot remove

InnoDB: the .ibd file, you can set innodb_force_recovery > 0 in my.cnf

InnoDB: and force InnoDB to continue crash recovery here.

140610 11:52:46 mysqld_safe mysqld from pid file /var/lib/mysql/run/mysql.pid ended

第一处标黄，提示是数据库没有正常关闭

第二处标蓝，提示正在从.ibd files读取tablespace information

第三处标红，就是开始error的地方，大概意思就是读取不到raildb这个库的tablespace

下边说的就是一些处理这个问题的方法，就不一一翻译了

最后我感觉是因为断电之前，mysql没有正常关闭，造成了raildb这个库的一些异常，我采用的解决方法是在innoDB，强制覆盖

Vi /etc/my.cof  增加一行      innodb_force_recovery= 1

然后删除log里边的mysql-bin.index 这个文件           rm -rf mysql-bin.index

之后重启mysql

OH YE!