SQL Server 2008 Administration in Action

16.1. Resource Governor overview

A common (and unfortunate) situation that DBAs often encounter in production systems is a single runaway query that flatlines server performance to the detriment of all users. Unless the offending query can be identified and killed, users are effectively at the mercy of the query completing. To make matters worse, there's nothing stopping the same query from occurring over and over again, with the end result being an unpredictable experience for end users and a frustrating one for DBAs.

In previous versions of SQL Server, resources could be constrained at an instance level with configuration settings such as CPU affinity and maximum memory, but such settings are coarse grained and don't apply to individual users ...