mysql主库清理数据，从库保留

[size=small]因为业务需要，想在mysql主库清理一些数据，但从库想要保留，根据网友介绍，可以根据binlog跳过清理的命令

1.确保主从同步的情况下，主库开始操作
mysql> flush logs; --刷新日志，切换一个新的binlog日志，比较小，后面修改就会方便些
Query OK, 0 rows affected (0.21 sec)

mysql> show master status \G
*************************** 1. row ***************************
File: mysql-bin.000039 --这里的binlog位置后面不会用到
Position: 33958
Binlog_Do_DB:
Binlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.03 sec)


2.从库停止同步 ---第1.2步尽量要快速操作
mysql> stop slave;
Query OK, 0 rows affected (0.05 sec)

mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.168.1.196
Master_User: repli
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000039
Read_Master_Log_Pos: 488906
Relay_Log_File: mysql-relay-bin.000016
Relay_Log_Pos: 489119
Relay_Master_Log_File: mysql-bin.000039
Slave_IO_Running: No
Slave_SQL_Running: No

3.主库清空数据

mysql> truncate table t2; 步骤a
Query OK, 0 rows affected (0.46 sec)

mysql> show master status \g 步骤b
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000039 | 1942762 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.06 sec)

/usr/local/mysql/bin/mysqlbinlog mysql-bin.000039 >000039.sql 步骤c

4.编辑000039.sql，删掉truncate语句
truncate table t2 /*!*/; ---删掉的内容

查找1942762 找不到该位置的话，可能会丢失数据，因此前面的三步abc一定要注意顺序！最好sql里面是包含这个位置信息的，然后删掉后面的内容，避免后面日志应用的时候，重复操作。

end_log_pos 1942762 将这个位置后面的内容全部干掉！


5.从库恢复
/usr/local/mysql/bin/mysql -umydba -p
source /root/000039.sql
mysql> change master to master_log_file='mysql-bin.000039',master_log_pos=1942762;
Query OK, 0 rows affected (0.19 sec)

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.1.196
Master_User: repli
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000039
Read_Master_Log_Pos: 10009221
Relay_Log_File: mysql-relay-bin.000002
Relay_Log_Pos: 8066779
Relay_Master_Log_File: mysql-bin.000039
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
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: 10009221
Relay_Log_Space: 8066986
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: 1
Master_UUID: 701cbadc-ba33-11e5-9091-305a3a78baf2
Master_Info_File: /usr/local/mysql/data/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)

---主从同步，跳过了truncate这个命令

6.验证
主库：
mysql> select * from t2;
Empty set (0.00 sec)


从库：
mysql> select * from t2;
+----+
| id |
+----+
| 1 |
| 2 |
| 3 |
| 4 |
| 5 |
+----+
5 rows in set (0.00 sec)[/size] 阅读更多