A quick solution to a common problem: your MySQL server has thousands of connections, some or most are not persistent. Unless you say otherwise, MySQL will check connections hostnames against the system DNS server. While this is generally not a problem with low traffic, when you are dealing with many concurrent connections you are not only wasting cycles with DNS name resolve, you may also overwhelm or alert your DNS server/provider. The solution? Set skip-name-resolve in the my.cnf file and MySQL will run the connections off of their IP address instead of the DNS name that it resolves to.