Mysql master-slave Mechanism

Mysql master-slave Mechanism

Mysql master-slave replication Principle

1) on the mysql master database, the changes are recorded in the binary log.

2) on the mysql slave database, the IO thread copies the binary log in the mysql master database to the relay log.
Mysql starts an IO thread from the database, opens a connection to the mysql master database, and starts dump of binlong to read events in the binlog;
If the master database is connected, the IO thread will sleep and wait for the master database to generate new events, and then the IO thread will write these events into the replay log.

3) on the mysql slave database, the SQL thread rewrites the events in the relay log (replay log) to update the data in the slave database, thus maintaining data consistency with the mysql master database.