mysql报错Ignoring the redo log due to missing MLOG_CHECKPOINT between
mysql版本：5.7.19
系统版本：centos7.3
由于周未公司断电，跑在vmware虚拟机上的mysql挂掉，无法重启
启动mysql的时候，error log的信息如下
--15T11::46.562061+: [ERROR] InnoDB: Ignoring the redo log due to missing MLOG_CHECKPOINT between the checkpoint and the end .
--15T11::46.562090+: [ERROR] InnoDB: Plugin initialization aborted with error Generic error
--15T11::47.062885+: [ERROR] Plugin 'InnoDB' init function returned error.
--15T11::47.062936+: [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
--15T11::47.062945+: [ERROR] Failed to initialize plugins.
--15T11::47.062951+: [ERROR] Aborting --15T11::47.062962+: [Note] Binlog end
在redo log里找不到checkpoint点，innodb引擎启动失败
解决办法有两个
第一个
设置innodb_force_recovery=6，然后启动mysql，能够顺利启动mysql
error log信息如下
--15T12::25.235397+: [Warning] 'db' entry 'sys mysql.sys@localhost' ignored in --skip-name-resolve mode.
--15T12::25.235408+: [Warning] 'proxies_priv' entry '@ root@localhost' ignored in --skip-name-resolve mode.
--15T12::25.235540+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`time_zone_leap_second` in the cache. Attempting to load the tablespace with space id
--15T12::25.256456+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`time_zone_name` in the cache. Attempting to load the tablespace with space id
--15T12::25.258414+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`time_zone` in the cache. Attempting to load the tablespace with space id
--15T12::25.263576+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`time_zone_transition_type` in the cache. Attempting to load the tablespace with space id
--15T12::25.267569+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`time_zone_transition` in the cache. Attempting to load the tablespace with space id
--15T12::25.272648+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`servers` in the cache. Attempting to load the tablespace with space id
--15T12::25.276466+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`slave_master_info` in the cache. Attempting to load the tablespace with space id
--15T12::25.280225+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`slave_relay_log_info` in the cache. Attempting to load the tablespace with space id
--15T12::25.286619+: [ERROR] InnoDB: Failed to find tablespace for table `mysql`.`slave_worker_info` in the cache. Attempting to load the tablespace with space id
--15T12::25.292450+: [ERROR] Error writing master configuration.
--15T12::25.292468+: [ERROR] Error reading master configuration.
--15T12::25.294535+: [Warning] Recovery from master pos and file mysql-bin. for channel ''. Previous relay log pos and relay log file had been set to , /data/mysql/mysql3306/logs/mysql-relay. respectively.
--15T12::25.294643+: [ERROR] Error writing relay log configuration.
--15T12::25.294656+: [ERROR] Error reading relay log configuration.
--15T12::25.294983+: [ERROR] Slave: Failed to initialize the master info structure for channel ''; its record may still be present in 'mysql.slave_master_info' table, consider deleting it.
--15T12::25.294996+: [ERROR] Failed to create or recover replication info repositories.
--15T12::25.295000+: [Note] Some of the channels are not created/initialized properly. Check for additional messages above. You will not be able to start replication on those channels until the issue is resolved and the server restarted.
由于损坏的这个库是从库，所以显示无法初始化master info表
由于mysql库里有几个表都显示找不到表空间，那么会存在丢失数据的风险
第二个
按照网上说的，把实例的所有ib_logfilex文件删除，再启动mysql，能够顺利启动
参照：http://blog.****.net/weiwangsisoftstone/article/details/52954228
error log信息如下
--15T11::17.694175+: [Note] Server socket created on IP: '::'.
--15T11::17.696000+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.696018+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.696287+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.696300+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.696535+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.696551+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.697469+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.697485+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.697809+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.697821+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.698049+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.698061+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.700092+: [Warning] 'user' entry 'root@localhost' ignored in --skip-name-resolve mode.
--15T11::17.700140+: [Warning] 'user' entry 'mysql.session@localhost' ignored in --skip-name-resolve mode.
--15T11::17.700153+: [Warning] 'user' entry 'mysql.sys@localhost' ignored in --skip-name-resolve mode.
--15T11::17.701714+: [Warning] 'db' entry 'performance_schema mysql.session@localhost' ignored in --skip-name-resolve mode.
--15T11::17.701727+: [Warning] 'db' entry 'sys mysql.sys@localhost' ignored in --skip-name-resolve mode.
--15T11::17.701881+: [Warning] 'proxies_priv' entry '@ root@localhost' ignored in --skip-name-resolve mode.
--15T11::17.702485+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.702502+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.702718+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.702741+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
--15T11::17.702962+: [ERROR] InnoDB: Page [page id: space=, page number=] log sequence number is in the future! Current system log sequence number .
--15T11::17.702974+: [ERROR] InnoDB: Your database may be corrupt or you may have copied the InnoDB tablespace but not the InnoDB log files. Please refer to http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html for information about forcing recovery.
按照报错信息，数据库也是无法回滚到之前一致性状态，有丢数据风险
总结
一般来说，mysql有坏块或者服务器异常关机
解决方法
1、在my.cnf里设置innodb_force_recovery=1 ，如果1不行改成2，最大是6 ，然后启动mysql， 将数据dump出来再 导入到新的实例
2、根据主键id ，逐个区间去导出，用mysqldump -w where条件，再导入到新实例
innodb_force_recovery影响整个innodb存储引擎的恢复状况，该值默认为0，表示当需要恢复时，需要执行所有的恢复操作，当不能进行有效恢复时，如数据页发生了corruption，mysql数据库可能宕机，并把错误写入错误日志中。
innodb_force_recovery=6表示mysql数据库已经有比较严重的损坏，就算把数据dump出来也不能保证dump出来的数据是没有问题的
最后建议选择第一个解决办法修改innodb_force_recovery的方法来恢复mysql，而不要选择第二个办法