延遲應用主要用於防範邏輯錯誤，如主庫誤修改、誤刪除等，從庫在設定時間內，還沒有應用這些錯誤的SQL，則可以在從庫獲取誤操作之前的資料。
Mysql透過指定從庫的master_delay選項來實現延遲應用。

1、安裝Mysql並配置主從
參考http://blog.itpub.net/28536251/viewspace-2138854/分別在兩節點安裝Mysql。
參考http://blog.itpub.net/28536251/viewspace-2138928/或者http://blog.itpub.net/28536251/viewspace-2139007/配置主從。

2、從庫配置延遲應用
(root@localhost)[(none)] stop slave sql_thread;
Query OK, 0 rows affected (0.15 sec)

(root@localhost)[(none)] change master to master_delay=60;
Query OK, 0 rows affected (0.02 sec)
#從庫延遲60秒。

(root@localhost)[(none)] start slave sql_thread;
Query OK, 0 rows affected (0.04 sec)

3、測試
主庫：
(root@localhost)[test] insert into tb1 values(3);
Query OK, 1 row affected (0.33 sec)

從庫：
(root@localhost)[(none)] show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 10.163.84.16
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 1298
Relay_Log_File: dbrac17-relay-bin.000003
Relay_Log_Pos: 594
Relay_Master_Log_File: mysql-bin.000002
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: 1024
Relay_Log_Space: 1839
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: 4
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: 8416
Master_UUID: 3de828ce-354c-11e7-9f0b-0050568a4cf6
Master_Info_File: /usr/local/mysql/data/master.info
SQL_Delay: 60
SQL_Remaining_Delay: 56
Slave_SQL_Running_State: Waiting until MASTER_DELAY seconds after master executed event
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)

#SQL_Delay: 60表示延遲60秒。
#SQL_Remaining_Delay: 56表示還有56秒才開始應用日誌。

1分鐘後檢視：
(root@localhost)[test] select * from tb1;
+------+
| id |
+------+
| 1 |
| 2 |
| 3 |
+------+
3 rows in set (0.00 sec)

Mysql配置從庫延遲應用

相關文章