connect_server() — this function is called each time a connection is made to MySQL Proxy from a client. You can use this function during load-balancing to intercept the original connection and decide which server the client should ultimately be attached to. If you do not define a special solution, then a simple round-robin style distribution is used by default.

read_handshake() — this function is called when the initial handshake information is returned by the server. You can capture the handshake information returned and provide additional checks before the authorization exchange takes place.

read_auth() — this function is called when the authorization packet (user name, password, default database) are submitted by the client to the server for authentication.

read_auth_result() — this function is called when the server returns an authorization packet to the client indicating whether the authorization succeeded.

read_query() — this function is called each time a query is sent by the client to the server. You can use this to edit and manipulate the original query, including adding new queries before and after the original statement. You can also use this function to return information directly to the client, bypassing the server, which can be useful to filter unwanted queries or queries that exceed known limits.

read_query_result() — this function is called each time a result is returned from the server, providing you have manually injected queries into the query queue. If you have not explicitly inject queries within the read_query() function then this function is not triggered. You can use this to edit the result set, or to remove or filter the result sets generated from additional queries you injected into the queue when using read_query().