MySQL master-slave replication principle

master database: Master
From database: Slave
Objective: To replicate the data from master to the slave database
Principle: The approximate process is slave by copying the Bin-log log file above the master to local, and then resolving it to an executable query statement in the local database.
The process is mainly three threads to complete: 1.master io thread, 2, slave io thread, and SQL thread first slave the request to master.
When Master's IO thread is responsible for converting data to a bin-log log file, slave io line subroutines to master will be transferred from the specified log file
A location in which to begin copying a later file, the log file is locked, but the lock time can be ignored, returned to slave from the library in the relay log file, the SQL engine detects that the relay log has changed, Parse to translate it into an executable SQL statement inserted into the database.