问题背景：
最近在测试ProxySQL+MHA实现MySQL读写分离+高可用，发现用于复制的密码忘记了，于是乎。。。
操作步鄹：
1、首先在主库修改用于复制的账号密码
root@localhost:mysql.sock 11:15:15 [(none)]>set password for 'replica_user'@'%'=password('654321');Query OK, 0 rows affected, 1 warning (0.00 sec) 2、在从库执行
root@localhost:mysql.sock 04:50:09 [tom]>stop slave;Query OK, 0 rows affected (0.01 sec)root@localhost:mysql.sock 04:50:21 [tom]>change master to master_host='10.0.0.6', master_user='replica_user', master_password='654321';Query OK, 0 rows affected, 2 warnings (0.04 sec)root@localhost:mysql.sock 04:50:33 [tom]>start slave;Query OK, 0 rows affected (0.01 sec)
如果是线上环境就比较悲剧了，为什么会这样呢？
Last_SQL_Errno: 1007 Last_SQL_Error: Error 'Can't create database 'tom'; database exists' on query. Default database: 'tom'. Query: 'create database tom'
看看官方的解释：https://dev.mysql.com/doc/refman/5.7/en/change-master-to.html
问题解决：
1、常见操作
root@localhost:mysql.sock 11:44:34 [tom]>stop slave;Query OK, 0 rows affected (0.01 sec)root@localhost:mysql.sock 11:44:38 [tom]>change master to master_user='replica_user', master_password='654321';Query OK, 0 rows affected, 2 warnings (0.02 sec)root@localhost:mysql.sock 11:44:46 [tom]>start slave;Query OK, 0 rows affected (0.02 sec)root@localhost:mysql.sock 11:44:49 [tom]>show slave status\G......Slave_IO_Running: Yes Slave_SQL_Running: Yes......
2、你也可以偷个懒
root@localhost:mysql.sock 05:19:12 [tom]>stop slave;Query OK, 0 rows affected (0.01 sec)root@localhost:mysql.sock 05:19:17 [tom]>change master to master_password='123456';Query OK, 0 rows affected, 2 warnings (0.04 sec)root@localhost:mysql.sock 05:19:38 [tom]>start slave;Query OK, 0 rows affected (0.01 sec)root@localhost:mysql.sock 05:19:41 [tom]>show slave status\G......Slave_IO_Running: Yes Slave_SQL_Running: YesSeconds_Behind_Master: 0......
3、或者你也可以
root@localhost:mysql.sock 11:52:34 [tom]>stop slave;Query OK, 0 rows affected (0.00 sec)root@localhost:mysql.sock 11:52:39 [tom]>change master to master_host='xxxx', -> master_port=xxxx, -> master_user='xxxx', -> master_password='xxxx', -> master_log_file='xxxx', -> master_log_pos=xxxx;Query OK, 0 rows affected, 2 warnings (0.03 sec)root@localhost:mysql.sock 11:53:09 [tom]>start slave;Query OK, 0 rows affected (0.01 sec)
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