MySQL: Slave Status - SECONDS_BEHIND_MASTER

We often execute the below command to check the replication status:

mysql> SHOW SLAVE STATUS \G

This will show all the details regarding replication. Out of which, the field SECONDS_BEHIND_MASTER is the one is the curious one.

It is the time in Seconds, which indicates actual amount of lag between Master and Slave.

In actual words, it's the calculation in seconds between the relay log's latest query event time stamp(which is already executed on master and queued on slave) and the current time stamp of the slave.

So, if the time set on Master's host and Slave's host are different, then, you'll see a scary value for this field.