MySQL is a popular RDBMS which is used in numerous projects. As a developer of Percona Server and engineer at Mail.Ru Target, I will tell you about unfortunate solutions for replication in MySQL, explain its internals, showcase the design faults and implementation of multi-threaded replication in the 5.7 version of the server. After this talk you will understand why such replication is a failure, how it should've been implemented instead and why PostgreSQL has avoided these pitfalls.<br /> <br /> We will discuss:<br /> - what is a asynchronous replication;<br /> - how does asynchronous replication function in MySQL;<br /> - what kinds of design flaws were made;<br /> - how these flaws manifest itself during database performance;<br /> - why these flaws prohibit proper utilization;<br /> - why parallel replication of MySQL 5.7 does not solve these issue, but only introduce the new ones;<br /> - how PostgreSQL avoids such problems.