mysql突然启动不起来了
mysql.ini配置也没发生更改过，替换初始的mysql.ini文件后也报一样的错。3306端口也没被占用。
2018-01-02 13:46:35 7fffaa5a6340 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 ./ridu/rd_indexpage.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.
方法1（推荐使用）
删除data目录下的ib_logfile0和ib_logfile1文件，如果是xampp的的话路径在/Applications/XAMPP/xamppfiles/var/mysql下，亲测好用
方法2
如果上面方法1不好使的话，就只能在配置文件里加这个innodb_force_recovery=4强制启动
然后尽快导出能导出的数据
