MySQL主从复制之延迟型数据复制
让MySQL拓扑中的从节点延迟适当的时间,可以帮助避免在主节点上发生的灾难性的错误。
MASTER_DELAY这个属性指定SQL_THREAD会在从节点上暂定多长时间,时间以秒为单位。默认值为0,上限为68年。
mysql> stop slave;
Query OK, 0 rows affected (0.06 sec)
mysql> change master to master_delay=20;
Query OK, 0 rows affected (0.01 sec)
mysql> start slave;
可以看到SQL_Delay: 20
下边做一个测试:
在主节点对测试表做truncate
在从节点查看表信息
发现从节点此表数据刚开始并没有被清理,20S之后数据才被清理掉。
在主库删除测试表
在从库查看表是否存在
一段时间之后,测试表才被删除。
名称栏目:MySQL主从复制之延迟型数据复制
文章源于:http://myzitong.com/article/jdoohh.html
MASTER_DELAY这个属性指定SQL_THREAD会在从节点上暂定多长时间,时间以秒为单位。默认值为0,上限为68年。
mysql> stop slave;
Query OK, 0 rows affected (0.06 sec)
mysql> change master to master_delay=20;
Query OK, 0 rows affected (0.01 sec)
mysql> start slave;
点击(此处)折叠或打开
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mysql> stop slave;
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Query OK, 0 rows affected (0.01 sec)
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mysql> change master to master_delay=20 ;
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Query OK, 0 rows affected (0.02 sec)
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mysql> start slave;
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Query OK, 0 rows affected (0.02 sec)
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mysql> show slave status \G
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*************************** 1. row ***************************
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Slave_IO_State: Waiting for master to send event
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Master_Host: 192.168.8.57
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Master_User: repl
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Master_Port: 3306
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Connect_Retry: 10
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Master_Log_File: mysql-bin.000021
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Read_Master_Log_Pos: 154
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Relay_Log_File: relay-log.000002
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Relay_Log_Pos: 320
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Relay_Master_Log_File: mysql-bin.000021
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Slave_IO_Running: Yes
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Slave_SQL_Running: Yes
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Replicate_Do_DB:
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Replicate_Ignore_DB:
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Replicate_Do_Table:
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Replicate_Ignore_Table:
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Replicate_Wild_Do_Table:
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Replicate_Wild_Ignore_Table:
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Last_Errno: 0
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Last_Error:
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Skip_Counter: 0
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Exec_Master_Log_Pos: 154
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Relay_Log_Space: 521
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Until_Condition: None
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Until_Log_File:
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Until_Log_Pos: 0
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Master_SSL_Allowed: No
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Master_SSL_CA_File: /usr/local/mysql/certs/ca-cert.pem
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Master_SSL_CA_Path:
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Master_SSL_Cert: /usr/local/mysql/certs/client-cert.pem
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Master_SSL_Cipher:
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Master_SSL_Key: /usr/local/mysql/certs/client-key.pem
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Seconds_Behind_Master: 0
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Master_SSL_Verify_Server_Cert: No
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Last_IO_Errno: 0
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Last_IO_Error:
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Last_SQL_Errno: 0
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Last_SQL_Error:
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Replicate_Ignore_Server_Ids:
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Master_Server_Id: 1
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Master_UUID: 9ad24233-aeef-11e7-aa1b-080027768e58
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Master_Info_File: mysql.slave_master_info
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SQL_Delay: 20
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SQL_Remaining_Delay: NULL
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Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
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Master_Retry_Count: 86400
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Master_Bind:
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Last_IO_Error_Timestamp:
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Last_SQL_Error_Timestamp:
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Master_SSL_Crl:
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Master_SSL_Crlpath:
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Retrieved_Gtid_Set:
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Executed_Gtid_Set:
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Auto_Position: 0
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Replicate_Rewrite_DB:
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Channel_Name:
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Master_TLS_Version:
- 1 row in set (0.00 sec)
下边做一个测试:
在主节点对测试表做truncate
点击(此处)折叠或打开
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mysql> show tables;
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+----------------+
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| Tables_in_test |
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+----------------+
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| tb_admin |
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| tb_admin_bak |
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+----------------+
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2 rows in set (0.00 sec)
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mysql> truncate table tb_admin_bak;
- Query OK, 0 rows affected (0.02 sec)
点击(此处)折叠或打开
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mysql> select count(*) from tb_admin_bak;
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+----------+
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| count(*) |
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+----------+
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| 1 |
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+----------+
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1 row in set (0.02 sec)
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mysql> select count(*) from tb_admin_bak;
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+----------+
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| count(*) |
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+----------+
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| 1 |
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+----------+
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1 row in set (0.00 sec)
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mysql> show full processlist \G
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*************************** 1. row ***************************
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Id: 3
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User: root
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Host: localhost
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db: test
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Command: Query
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Time: 0
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State: starting
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Info: show full processlist
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*************************** 2. row ***************************
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Id: 8
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User: system user
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Host:
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db: NULL
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Command: Connect
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Time: 334
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State: Waiting for master to send event
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Info: NULL
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*************************** 3. row ***************************
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Id: 9
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User: system user
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Host:
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db: NULL
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Command: Connect
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Time: 100
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State: Waiting until MASTER_DELAY seconds after master executed event
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Info: NULL
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3 rows in set (0.00 sec)
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mysql> select count(*) from tb_admin_bak;
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+----------+
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| count(*) |
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+----------+
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| 0 |
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+----------+
- 1 row in set (0.00 sec)
在主库删除测试表
点击(此处)折叠或打开
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mysql> drop table tb_admin_bak;
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Query OK, 0 rows affected (0.06 sec)
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mysql> show tables;
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+----------------+
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| Tables_in_test |
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+----------------+
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| tb_admin |
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+----------------+
- 1 row in set (0.00 sec)
点击(此处)折叠或打开
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mysql> show tables;
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+----------------+
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| Tables_in_test |
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+----------------+
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| tb_admin |
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| tb_admin_bak |
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+----------------+
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2 rows in set (0.00 sec)
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mysql> show tables;
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+----------------+
-
| Tables_in_test |
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+----------------+
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| tb_admin |
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| tb_admin_bak |
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+----------------+
-
2 rows in set (0.00 sec)
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mysql> show tables;
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+----------------+
-
| Tables_in_test |
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+----------------+
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| tb_admin |
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| tb_admin_bak |
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+----------------+
-
2 rows in set (0.00 sec)
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mysql> show tables;
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+----------------+
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| Tables_in_test |
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+----------------+
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| tb_admin |
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| tb_admin_bak |
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+----------------+
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2 rows in set (0.00 sec)
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mysql> show tables;
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+----------------+
-
| Tables_in_test |
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+----------------+
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| tb_admin |
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| tb_admin_bak |
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+----------------+
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2 rows in set (0.00 sec)
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mysql> show tables;
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+----------------+
-
| Tables_in_test |
-
+----------------+
-
| tb_admin |
-
| tb_admin_bak |
-
+----------------+
-
2 rows in set (0.00 sec)
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mysql> show tables;
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+----------------+
-
| Tables_in_test |
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+----------------+
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| tb_admin |
-
| tb_admin_bak |
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+----------------+
-
2 rows in set (0.00 sec)
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mysql> show tables;
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+----------------+
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| Tables_in_test |
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+----------------+
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| tb_admin |
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+----------------+
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1 row in set (0.00 sec)
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mysql> show tables;
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+----------------+
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| Tables_in_test |
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+----------------+
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| tb_admin |
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+----------------+
- 1 row in set (0.00 sec)
名称栏目:MySQL主从复制之延迟型数据复制
文章源于:http://myzitong.com/article/jdoohh.html