The battle between email admins and spammers is an ongoing arms race. The spammers are at a disadvantage because by and large, they have to rely on exploiting vulnerable systems to send their mail. With the ever growing size of botnets, they have a pretty large pool of exploited systems to send from, but Postfix can be configured to weed out most of that.
It’s all too common for me to come across a box that is hopelessly overloaded with Apache requests and MySQL queries. Sometimes, it takes some brute force to keep the whole box from going under. When all else fails, I use the following one-liner to kill off all of those queries that have been running for too long.