Manually replacing MySQL database files causes MySQL to fail to start

The server quit without updating PID file (/usr/local/mysql/data/mysql.pid

This error almost swept all MySQL startup error;

Check the SQL error log

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 can be restore it from a backup,
Innodb:then you can remove the. ibd file, and InnoDB would 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, can set innodb_force_recovery > 0 in MY.CNF
Innodb:and force InnoDB to continue crash recovery here.
160721 12:14:43 mysqld_safe mysqld from PID File/usr/local/mysql/data/mysql.pid ended

First InnoDB;

The person

If The table is not needed, or can be restore it from a backup,
Then you can remove the. ibd file, and InnoDB would do a normal
Crash recovery and ignore that table.

Because I used a InnoDB table engine database to overwrite another useless database file;

RM-RF the wrong table

Manually replacing MySQL database files causes MySQL to fail to start