One of the features that has helped make MySQL so popular over the years is the support for replication which allows you to have a MySQL instance that automatically receives the updates from its source and applies them. A recurring task for database administrators is to work on improving the performance of the replication. Over the years, there have been many improvements to MySQL replication including some that can help you improve the replication performance. This chapter will start out providing a high-level overview of replication with the purpose of introducing terminology and a test setup that will be used for the section on replication monitoring. The other half of the chapter discusses how the performance of the connection and applier threads can be improved and how replication can be used to offload work to a replica.