MySQL Reference Manual

Replication in MySQL

This section describes the various replication features in MySQL. It serves as a reference to the options available with replication. You will be introduced to replication and learn how to implement it. Toward the end, there are some frequently asked questions and descriptions of problems and how to solve them.

We suggest that you visit our web site at http://www.mysql.com/ often and read updates to this section. Replication is constantly being improved, and we update the manual frequently with the most current information.

Introduction

One way replication can be used is to increase both robustness and speed. For robustness you can have two systems and can switch to the backup if you have problems with the master. The extra speed is achieved by sending a part of the non-updating queries to the replica server. Of course, this only works if non-updating queries dominate, but that is the normal case.

Starting in Version 3.23.15, MySQL supports one-way replication internally. One server acts as the master, while the other acts as the slave. Note that one server could play the roles of master in one pair and slave in the other. The master server keeps a binary log of updates (see Section 4.9.4) and an index file to binary logs to keep track of log rotation. The slave, upon connecting, informs the master where it left off since the last successfully propagated update, catches up on the updates, and then blocks and waits for the master to notify it of the new updates. ...