Debezium series: Show slave status view the possible different situations of master-slave delay

One 、 Master node view show slave status

• It returns a null value

Two 、 View from the node show slave status

Focus on the following three indicators

• Slave_IO_Running
• Slave_SQL_Running
• Seconds_Behind_Master

Normal values are as follows ：

Slave_IO_Running	Slave_SQL_Running	Seconds_Behind_Master
Yes	Yes	0

3、 ... and 、 Master node view show slave status Parameters Seconds_Behind_Master The value is Null

Slave_IO_Running	Slave_SQL_Running	Seconds_Behind_Master
Yes	Yes	Null

• Seconds_Behind_Master The value of is Null, It may be that the database of this master node used to be the slave node of other databases
• reset slave all Empty the information from the library , Check it again show slave status