Mysql主从复制中断一例
收到mysql主从中断报警，马上登上服务器查看，发现是中继日志损坏。
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Show slave status\G,提示中继日志损坏。
Relay log read failure: Could not parse relay log event entry. The possible reasons are: the master‘s binary log is corrupted (you can check this by running ‘mysqlbinlog‘ on the binary log), the slave‘s relay log is corrupted (you can check this by running ‘mysqlbinlog‘ on the relay log), a network problem, or a bug in the master‘s or slave‘s MySQL code. If you want to check the master‘s binary log or slave‘s relay log, you will be able to know their names by issuing ‘SHOW SLAVE STATUS‘ on this slave.
2. 从MySQL5.5.X版本开始，增加了relay_log_recovery参数，这个参数的作用是：当slave从库宕机后，假如relay-log损坏了，导致一部分中继日志没有处理，则自动放弃所有未执行的relay-log，并且重新从master上获取日志，这个参数是默认关闭的。做主从的时候没有开启这项参数。修改my.cnf，添加这两项。（skip-slave-start ，mysql服务启动跳过自动启动主从复制，以免产生新的问题）并重启mysql，然后手工启动主从复制。
relay_log_recovery = 1
skip-slave-start = 1
3.再查看Show slavestatus\G，同步已经恢复，正在应用中继日志，等同步完成之后，然后随机抽查一个表，数据一致
#########################################################
Relay_Master_Log_File: mysql-bin.000642
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
##############################################
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error: