MySQL主从故障修复
测试库：
192.168.1.2 主
192.168.1.3 从
192.168.1.4 主 4又是2的从库
192.168.1.5 从
有人修改了192.168.1.2和192.168.1.3的数据库参数后，重启数据库。
忘记了192.168.1.4又是192.168.1.2的从库，导致192.168.1.2和192.168.1.4的主从断掉。
并且在192.168.1.2上创建了新库还原数据删除等操作，导致192.168.1.4提示错误。
模拟如下：
通过从库查看主从状态：
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 172.16.33.243
Master_User: master
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000006
Read_Master_Log_Pos: 303
Relay_Log_File: relay-log.000005
Relay_Log_Pos: 340
Relay_Master_Log_File: mysql-bin.000006
Slave_IO_Running: Yes
Slave_SQL_Running: No
Replicate_Do_DB:
Replicate_Ignore_DB: test
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 1049
Last_Error: Error 'Unknown database 'sakila'' on query. Default database: 'sakila'. Query: 'create table sakila (id int,name varchar(2))'
Skip_Counter: 0
Exec_Master_Log_Pos: 194
Relay_Log_Space: 745
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 1049
Last_SQL_Error: Error 'Unknown database 'sakila'' on query. Default database: 'sakila'. Query: 'create table sakila (id int,name varchar(2))'
Replicate_Ignore_Server_Ids:
Master_Server_Id: 360360
1 row in set (0.00 sec)
记录下二进制日志的和点的位置：
Relay_Master_Log_File: mysql-bin.000006
Exec_Master_Log_Pos: 194
停掉从库的slave
mysql> stop slave;
Query OK, 0 rows affected (0.01 sec)
并在主库删除掉新建的库
mysql> drop database sakila;
Query OK, 1 row affected (0.04 sec)
重新进行主从复制
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000006 | 388 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
mysql> change master to master_host='192.168.1.2',master_port=3306,master_user='master',master_password='123456',master_log_file='mysql-bin.000006',master_log_pos=388;
Query OK, 0 rows affected (0.01 sec)
mysql> start slave ;
Query OK, 0 rows affected (0.00 sec)
查看主从状态还提示原来的错误，使用sql_slave_skip_counter参数
mysql> show variables like '%skip%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| skip_external_locking | ON |
| skip_name_resolve | ON |
| skip_networking | OFF |
| skip_show_database | OFF |
| slave_skip_errors | OFF |
| sql_slave_skip_counter | 0 |
+------------------------+-------+
6 rows in set (0.00 sec)
默认为0
mysql> set global sql_slave_skip_counter = 1;
mysql> start slave;
还提示错误，继续
mysql> set global sql_slave_skip_counter = 1;
mysql> start slave;
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.2
Master_User: master
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000006
Read_Master_Log_Pos: 388
Relay_Log_File: relay-log.000002
Relay_Log_Pos: 253
Relay_Master_Log_File: mysql-bin.000006
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB: test
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 388
Relay_Log_Space: 403
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
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:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 360360
最后在192.168.1.2上重新建库并还原数据