演示大事物导致复制延时

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master：

#主库开始一个大事物等待结束传送到从库上：

root@localhost [employees]>alter table salaries engine=innodb;

Query OK, 0 rows affected (24.78 sec)

slave:

#从库处于延迟的状态：

root@localhost [employees]>show slave status\G

*************************** 1. row ***************************

Slave_IO_State: Waiting for master to send event

Master_Host: 192.168.91.23

Master_User: repl

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: MySQL-bin.000016

Read_Master_Log_Pos: 740 --从库的io_thread已经读取到主库的binlog从原来的557增长到740

Relay_Log_File: relay-bin.000040

Relay_Log_Pos: 770

Relay_Master_Log_File: mysql-bin.000016

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: 557 --但是从库的sql_thread还没有重放结束，exec_master_log_pos还没有变化

Relay_Log_Space: 76001152

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: 29 --可以看到从库已经延迟主库29s

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: 330623

Master_UUID: b30cdc47-216a-11e7-95a8-000c29565380

Master_Info_File: mysql.slave_master_info

SQL_Delay: 0

SQL_Remaining_Delay: NULL

Slave_SQL_Running_State: altering table --看到从库的sql_thread正在alter table动作

Master_Retry_Count: 86400

Master_Bind:

Last_IO_Error_Timestamp:

Last_SQL_Error_Timestamp:

Master_SSL_Crl:

Master_SSL_Crlpath:

Retrieved_Gtid_Set: b30cdc47-216a-11e7-95a8-000c29565380:2-1518 --表示从库已经读取到1518这个事物，但是还没有重放结束

Executed_Gtid_Set: b30cdc47-216a-11e7-95a8-000c29565380:1-1517

Auto_Position: 1

Replicate_Rewrite_DB:

Channel_Name:

Master_TLS_Version:

#从库大事物结束后的状态：

root@localhost [employees]>show slave status\G\