问题：
mysql启动失败
查看错误日志
2017-12-16 9:48:19 16000 [ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace mysql/gtid_slave_pos uses space ID: 3 at filepath: .\mysql\gtid_slave_pos.ibd. Cannot open tablespace mysql/slave_relay_log_info which uses space ID: 3 at filepath: .\mysql\slave_relay_log_info.ibd InnoDB: Error: could not open single-table tablespace file .\mysql\slave_relay_log_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.
解决办法：
在mysql的配置文件my.ini中添加
innodb_force_recovery = 1