To check the status of a slave, run the SHOW SLAVE STATUS command.
mysql> SHOW SLAVE STATUS\G;
Something like below will be showing:
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.0.100
Master_User: slaveuser_for_s2
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000010
Read_Master_Log_Pos: 98
Relay_Log_File: slave-relay.000002
Relay_Log_Pos: 235
Relay_Master_Log_File: mysql-bin.000010
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: exampledb
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: 98
Relay_Log_Space: 235
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
1 row in set (0.01 sec)
It is important that both Slave_IO_Running and Slave_SQL_Running have the value YES in the output.
Slave IO Thread
------------------
Master_Log_File : The name of the binlog file from the master that slave IO thread is “working on”. It is not the name of a relay log on the slave
Read_Master_Log_Pos : The position in the Master_Log_File that the slave IO thread has copied up to.
Relay_Log_File : Current relay log accepting new entries during replication
Relay_Log_Pos : Current position of the current relay log accepting new entries during replication
SQL Thread
-------------
Relay_Master_Log_File : The name of the binlog file from the master that SQL thread is “working on”. It is not the name of a relay log on the slave
Exec_Master_Log_Pos : The position in the Relay_Master_Log_File that the slave SQL thread has executed up to.