mysql意外关机后，mysql启动报错误：
The server quit without updating PID file.
查看mysql启动日志后发现错误告警如下：
2018-01-22 10:34:29 6904 [Warning] Using unique option prefix myisam_recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead.
2018-01-22 10:34:29 6904 [Note] Plugin 'FEDERATED' is disabled.
2018-01-22 10:34:29 7f713974f720 InnoDB: Warning: Using innodb_additional_mem_pool_size is DEPRECATED. This option may be removed in future releases, together with the option innodb_use_sys_malloc and with the InnoDB's internal memory allocator.
2018-01-22 10:34:29 6904 [Note] InnoDB: Using atomics to ref count buffer pool pages
2018-01-22 10:34:29 6904 [Note] InnoDB: The InnoDB memory heap is disabled
2018-01-22 10:34:29 6904 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2018-01-22 10:34:29 6904 [Note] InnoDB: Memory barrier is not used
2018-01-22 10:34:29 6904 [Note] InnoDB: Compressed tables use zlib 1.2.3
2018-01-22 10:34:29 6904 [Note] InnoDB: Using Linux native AIO
2018-01-22 10:34:29 6904 [Note] InnoDB: Using CPU crc32 instructions
2018-01-22 10:34:29 6904 [Note] InnoDB: Initializing buffer pool, size = 512.0M
2018-01-22 10:34:29 6904 [Note] InnoDB: Completed initialization of buffer pool
2018-01-22 10:34:29 6904 [Note] InnoDB: Highest supported file format is Barracuda.
2018-01-22 10:34:29 6904 [Note] InnoDB: The log sequence numbers 0 and 0 in ibdata files do not match the log sequence number 373452843 in the ib_logfiles!
2018-01-22 10:34:29 6904 [Note] InnoDB: Database was not shutdown normally!
2018-01-22 10:34:29 6904 [Note] InnoDB: Starting crash recovery.
2018-01-22 10:34:29 6904 [Note] InnoDB: Reading tablespace information from the .ibd files...
2018-01-22 10:34:29 6904 [ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace mysql/slave_worker_info uses space ID: 5 at filepath: ./mysql/slave_worker_info.ibd. Cannot open tablespace keycloak/AUTHENTICATOR_CONFIG which uses space ID: 5 at filepath: ./keycloak/AUTHENTICATOR_CONFIG.ibd
2018-01-22 10:34:29 7f713974f720 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 ./keycloak/AUTHENTICATOR_CONFIG.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.
解决方式：
InnoDB: 1) If there is a permission problem in the file and mysqld cannot # 如果是权限问题，添加相应的权限
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, #如果有备份的话可以删除.ibd文件，重新恢复即可
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 #如果不存在备份，必须要使用，就需要在my.cnf中添加设置innodb_force_recovery >0的值，如 innodb_force_recovery =1，修改后启动mysql即可
[mysqld]
innodb_force_recovery=1
InnoDB: the .ibd file, you can set innodb_force_recovery > 0 in my.cnf
InnoDB: and force InnoDB to continue crash recovery here.
