This section describes replication between MySQL servers based on the binary log file position method, where the MySQL instance operating as the master (the source of the database changes) writes updates and changes as “events” to the binary log. The information in the binary log is stored in different logging formats according to the database changes being recorded. Slaves are configured to read the binary log from the master and to execute the events in the binary log on the slave's local database.
Each slave receives a copy of the entire contents of the binary log. It is the responsibility of the slave to decide which statements in the binary log should be executed. Unless you specify otherwise, all events in the master binary log are executed on the slave. If required, you can configure the slave to process only events that apply to particular databases or tables.
You cannot configure the master to log only certain events.
Each slave keeps a record of the binary log coordinates: the file name and position within the file that it has read and processed from the master. This means that multiple slaves can be connected to the master and executing different parts of the same binary log. Because the slaves control this process, individual slaves can be connected and disconnected from the server without affecting the master's operation. Also, because each slave records the current position within the binary log, it is possible for slaves to be disconnected, reconnect and then resume processing.
The master and each slave must be configured with a unique ID
server-id option). In
addition, each slave must be configured with information about the
master host name, log file name, and position within that file.
These details can be controlled from within a MySQL session using
CHANGE MASTER TO statement on
the slave. The details are stored within the slave's master
info repository (see Section 17.2.4, “Replication Relay and Status Logs”).