MySQL Proxy transparently passes information between a client and a MySQL server. The proxy can audit the information flow in both directions and change it if necessary, which could be useful for protecting the MySQL server from malicious queries or for altering the information clients receive without actually making changes to the database. The proxy can also do load balancing between MySQL servers, and perform flow optimization by directing SELECT statements to read-only slave servers, which enhances MySQL scalability by allowing you to add more servers for read operations.