MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6

16.3.10 Delayed Replication

MySQL 5.7 supports delayed replication such that a slave server deliberately lags behind the master by at least a specified amount of time. The default delay is 0 seconds. Use the MASTER_DELAY option for CHANGE MASTER TO to set the delay to N seconds:

CHANGE MASTER TO MASTER_DELAY = N;

An event received from the master is not executed until at least N seconds later than its execution on the master. The exceptions are that there is no delay for format description events or log file rotation events, which affect only the internal state of the SQL thread.

Delayed replication can be used for several purposes:

START SLAVE and STOP SLAVE take effect immediately and ignore any delay. RESET SLAVE resets the delay to 0.

SHOW SLAVE STATUS has three fields that provide information about the delay:

When the slave SQL thread is waiting for the delay to elapse before executing an event, SHOW PROCESSLIST displays its State value as Waiting until MASTER_DELAY seconds after master executed event.