演示大事物导致复制延时
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\
*************************** 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
Relay_Log_File: relay-bin.000040
Relay_Log_Pos: 953
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: 740
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: 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: 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: 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: b30cdc47-216a-11e7-95a8-000c29565380:2-1518
Executed_Gtid_Set: b30cdc47-216a-11e7-95a8-000c29565380:1-1518
Auto_Position: 1
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
