There are two models of load balancing: transport and application layer. HAProxy is a great TCP load balancer, but it’s lack of SQL awareness effectively limits its ability to address certain scaling issues in distributed database environments. In the open source world, there’s been a few SQL-aware load balancers, namely MySQL Proxy, ProxySQL and MaxScale, but they all seemed to be in beta status and unfit for production use. So we were pretty excited when the MariaDB team released a GA version of MaxScale earlier this year. In this blog, we’ll have a look at MaxScale and see how it compares with HAProxy.