[MySQL] Error establishing a database connection

太久沒有管 MySQL 就會有奇怪的問題, 所以也不太確定問題的由來, 只能用土法解決

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/innodb_index_stats.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.

先直接講解法好了, 就是在 my.cnf 多設定一行
nnodb_force_recovery = 1

重啟 MySQL 後再註解掉就可以了


參考: http://linux-server-tutorial.blogspot.tw/2014/02/mysql-is-not-starting-operating-system.html