基本的M-S结构

现在master与slave主机数据一致：

mysql> select * from t1;
+------+
| id   |
+------+
|    1 |
|    2 |
|    4 |
+------+
3 rows in set (0.00 sec)

我们来模拟故障现象：

在master上，通过设置sql_log_bin来控制命令是否写入二进制日志中，运行命令：

set sql_log_bin=OFF;
insert into t1 values(5);
set sql_log_bin=ON;
insert into t1 values(6);

这样数据在master上是这样的：

而在slave上的数据是这样的：

mysql> select * from testdb.t1;
+------+
| id   |
+------+
|    1 |
|    2 |
|    4 |
|    6 |
+------+
4 rows in set (0.00 sec)

此时我们在master上执行操作：

update t1 set id=7 where id=5;
insert into t1 values(8);mysql> select * from t1;
+------+
| id   |
+------+
|    1 |
|    2 |
|    4 |
|    7 |
|    6 |
|    8 |
+------+
6 rows in set (0.00 sec)

我们查询一下slave上的数据：

mysql> select * from testdb.t1;
+------+
| id   |
+------+
|    1 |
|    2 |
|    4 |
|    6 |
+------+
4 rows in set (0.00 sec)

发现数据并没有被同步过来，我们来show一下slave

mysql> show slave status\G
*************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.203.135Master_User: replmonitorMaster_Port: 3306Connect_Retry: 60Master_Log_File: host2-bin.000002Read_Master_Log_Pos: 1146Relay_Log_File: host3-relay-bin.000003Relay_Log_Pos: 648Relay_Master_Log_File: host2-bin.000002Slave_IO_Running: YesSlave_SQL_Running: NoReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno: 1032Last_Error: Could not execute Update_rows event on table testdb.t1; Can't find record in 't1', Error_code: 1032; handler error HA_ERR_END_OF_FILE; the event's master log host2-bin.000002, end_log_pos 875Skip_Counter: 0Exec_Master_Log_Pos: 660Relay_Log_Space: 1595Until_Condition: NoneUntil_Log_File:Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_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: NoLast_IO_Errno: 0Last_IO_Error:Last_SQL_Errno: 1032Last_SQL_Error: Could not execute Update_rows event on table testdb.t1; Can't find record in 't1', Error_code: 1032; handler error HA_ERR_END_OF_FILE; the event's master log host2-bin.000002, end_log_pos 875Replicate_Ignore_Server_Ids:Master_Server_Id: 2Master_UUID: cd32a980-2a97-11e5-a344-000c2954ccdeMaster_Info_File: mysql.slave_master_infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State:Master_Retry_Count: 86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp: 150717 23:51:51Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set: cd32a980-2a97-11e5-a344-000c2954ccde:1-3Executed_Gtid_Set: cd32a980-2a97-11e5-a344-000c2954ccde:1Auto_Position: 1
1 row in set (0.00 sec)

此时我们查看一下错误日志：

2015-07-17 23:51:51 30750 [ERROR] Slave SQL: Could not execute Update_rows event on table testdb.t1; Can't find record in 't1', Error_code: 1032; handler error HA_ERR_END_OF_FILE; the event's master log host2-bin.000002, end_log_pos 875, Error_code: 1032
2015-07-17 23:51:51 30750 [Warning] Slave: Can't find record in 't1' Error_code: 1032
2015-07-17 23:51:51 30750 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with "SLAVE START". We stopped at log 'host2-bin.000002' position 660

提示我们在修改错误并重新启动slave，但关键在于如何修正错误，一般我们采用如下方法：

在从机slave上执行：

可以发现事务已经全部同步了，但现在数据却是不一致的。

这种适合在数据要求不高的情况下使用，如果后续还有其它数据操作，造成主从数据差异过大，就得用从主库的一个完整备份过来，再从某点开始做replication。