Mysql主從日常管理任務主要包括兩種:

查看復制狀態

復制任務控制

一、查看復制狀態

?要檢查主從復制當前的狀態，需要在從庫服務器上執行語句：

??

show?slave?status

?執行結果如下所示:

?

mysql>?show?slave?status\G ***************************?1.?row?***************************Slave_IO_State:?Waiting?for?master?to?send?eventMaster_Host:?192.168.200.20Master_User:?replicaMaster_Port:?3306Connect_Retry:?10Master_Log_File:?mysql-binlog.000017Read_Master_Log_Pos:?120Relay_Log_File:?mysql-relaylog.000007Relay_Log_Pos:?286Relay_Master_Log_File:?mysql-binlog.000017Slave_IO_Running:?YesSlave_SQL_Running:?YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno:?0Last_Error:Skip_Counter:?0Exec_Master_Log_Pos:?120Relay_Log_Space:?624Until_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:?0 Master_SSL_Verify_Server_Cert:?NoLast_IO_Errno:?0Last_IO_Error:Last_SQL_Errno:?0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id:?1Master_UUID:?e84592e0-0e5b-11e4-a5d3-000c29e88022Master_Info_File:?/usr/local/mysql/data/master.infoSQL_Delay:?0SQL_Remaining_Delay:?NULLSlave_SQL_Running_State:?Slave?has?read?all?relay?log;?waiting?for?the?slave?I/O?thread?to?update?itMaster_Retry_Count:?86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position:?0 1?row?in?set?(0.00?sec)

查詢結果報表中比較關鍵的幾個字段:

Slave_IO_Status: 從服務器的IO狀態。

Slave_IO_Runing: 從服務器IO線程是否正在運行，即從服務器是否正在讀取主服務的二進制日志。

Slave_SQL_Running:從服務器SQL線程是否正在運行,即服務器是夠正在執行中繼日志中的事件.

Last_IO_Error,Last_SQL_Error: IO和SQL線程最新遇到的錯誤.

Seconds_Behind_Master:從服務器SQL線程處理中繼日志的時間(秒),通常可以用來不精確性的評估主從

復制的延遲大小. 0 秒 意味著基本同步，數值越大意味著偏移量越大，同步延遲較高。

*_Log_*: 基本上都是和日志文件有關的信息，比如當前的二進制日志文件名稱、位置等，都很容易理

解.

也可以在主服務器上查看當前已經連接的從服務器的狀態，

包括以下語句:

show?processlist?show?slave?hosts

顯示效果如下所示:

?

mysql>?show?processlist\G ***************************?1.?row?***************************Id:?1User:?replicaHost:?192.168.200.21:40781db:?NULL Command:?Binlog?DumpTime:?1929State:?Master?has?sent?all?binlog?to?slave;?waiting?for?binlog?to?be?updatedInfo:?NULL ***************************?2.?row?***************************Id:?2User:?rootHost:?localhostdb:?NULL Command:?QueryTime:?0State:?initInfo:?show?processlist 2?rows?in?set?(0.00?sec)mysql>?show?slave?hosts; +-----------+------+------+-----------+--------------------------------------+ |?Server_id?|?Host?|?Port?|?Master_id?|?Slave_UUID???????????????????????????| +-----------+------+------+-----------+--------------------------------------+ |?????????2?|??????|?3306?|?????????1?|?624856ee-1d1c-11e4-8605-000c29972cfa?| +-----------+------+------+-----------+--------------------------------------+ 1?row?in?set?(0.00?sec)

在主從復制過程中，是從服務器主動去主服務器獲取二進制日志數據，因此從服務器控制復制過程，占

據主動地位，也因此在主服務器上查看Slave 狀態時報表信息量很少.

二、復制任務控制

啟停復制控制語句:

#啟動復制 mysql>?start?slave; #停止復制 mysql>?stop?slave;

"stop slave" 指令執行后，從服務器IO線程不再從主服務器讀取二進制日志文件并寫入到中繼日志，

?SQL 線程也不再從中繼日志讀取事件并執行事件語句。如果想單獨控制IO或者SQL線程，需要使用如

?下指令分別控制:

??

#停止IO線程 mysql>?stop?slave?io_thread; #停止SQL線程 mysql>?stop?slave?sql_thread;#分別啟用IO和SQL線程: mysql>?start?slave?io_thread; mysql>?start?slave?sql_thread;

模擬控制線程并查看主從復制狀態:

停止IO線程，并查看主從復制狀態:

mysql>?stop?slave?io_thread; Query?OK,?0?rows?affected?(0.09?sec)mysql>?show?slave?status\G ***************************?1.?row?***************************Slave_IO_State:Master_Host:?192.168.200.20Master_User:?replicaMaster_Port:?3306Connect_Retry:?10Master_Log_File:?mysql-binlog.000017Read_Master_Log_Pos:?120Relay_Log_File:?mysql-relaylog.000007Relay_Log_Pos:?286Relay_Master_Log_File:?mysql-binlog.000017Slave_IO_Running:?NoSlave_SQL_Running:?YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno:?0Last_Error:Skip_Counter:?0Exec_Master_Log_Pos:?120Relay_Log_Space:?624Until_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:?0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id:?1Master_UUID:?e84592e0-0e5b-11e4-a5d3-000c29e88022Master_Info_File:?/usr/local/mysql/data/master.infoSQL_Delay:?0SQL_Remaining_Delay:?NULLSlave_SQL_Running_State:?Slave?has?read?all?relay?log;?waiting?for?the?slave?I/O?thread?to?update?itMaster_Retry_Count:?86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position:?0 1?row?in?set?(0.00?sec)

可以看到Slave_IO_Status 狀態值為No,而Slave_SQL_Status 狀態值仍為 Yes.

Slave_IO_Status 也為空值了。

再停止SQL線程:

mysql>?stop?slave?sql_thread; Query?OK,?0?rows?affected?(0.10?sec)mysql>?show?slave?status\G ***************************?1.?row?***************************Slave_IO_State:Master_Host:?192.168.200.20Master_User:?replicaMaster_Port:?3306Connect_Retry:?10Master_Log_File:?mysql-binlog.000017Read_Master_Log_Pos:?120Relay_Log_File:?mysql-relaylog.000007Relay_Log_Pos:?286Relay_Master_Log_File:?mysql-binlog.000017Slave_IO_Running:?NoSlave_SQL_Running:?NoReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno:?0Last_Error:Skip_Counter:?0Exec_Master_Log_Pos:?120Relay_Log_Space:?624Until_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:?0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id:?1Master_UUID:?e84592e0-0e5b-11e4-a5d3-000c29e88022Master_Info_File:?/usr/local/mysql/data/master.infoSQL_Delay:?0SQL_Remaining_Delay:?NULLSlave_SQL_Running_State:Master_Retry_Count:?86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position:?0 1?row?in?set?(0.00?sec)

可以看到Slave_IO_Status 、Slave_SQL_Status 狀態值全為 No.

再次執行"start slave" 或者分別執行"start slave io_thread"和"start slave sql_thread":

mysql>?start??slave?; mysql>?show?slave?status\G ***************************?1.?row?***************************Slave_IO_State:?Waiting?for?master?to?send?eventMaster_Host:?192.168.200.20Master_User:?replicaMaster_Port:?3306Connect_Retry:?10Master_Log_File:?mysql-binlog.000017Read_Master_Log_Pos:?120Relay_Log_File:?mysql-relaylog.000008Relay_Log_Pos:?286Relay_Master_Log_File:?mysql-binlog.000017Slave_IO_Running:?YesSlave_SQL_Running:?YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno:?0Last_Error:Skip_Counter:?0Exec_Master_Log_Pos:?120Relay_Log_Space:?624Until_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:?0 Master_SSL_Verify_Server_Cert:?NoLast_IO_Errno:?0Last_IO_Error:Last_SQL_Errno:?0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id:?1Master_UUID:?e84592e0-0e5b-11e4-a5d3-000c29e88022Master_Info_File:?/usr/local/mysql/data/master.infoSQL_Delay:?0SQL_Remaining_Delay:?NULLSlave_SQL_Running_State:?Slave?has?read?all?relay?log;?waiting?for?the?slave?I/O?thread?to?update?itMaster_Retry_Count:?86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position:?0 1?row?in?set?(0.00?sec)

查看復制狀態，主從復制恢復正常.

轉載于:https://blog.51cto.com/magic3/1538469

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