Recently we had a small hiccup in our service; it was caused by our mysql replication configuration and a small mistake which was made a long time before. The lesson was learned, and now I show that to you.
MySQL replication is simple. The replica set’s primary server (aka. replication master) writes the events which affect the database to a binary log file, and slaves will apply that log on their datasets. The binary log can be statement-based, row-based or in mixed mode, the events can be either DML or DDL queries. Simple enough.