It is not every question that deserves an answer.
Publilius Syrus (a.k.a. Publius) Maxim 581
Computers are fast enough that they never have to be the bottleneck in a business process. When they turn out to be a bottleneck, solutions always exist. However, the solutions do not always take the form of answers to the question "How do I make this query return the same rows faster?" So far, this book has focused on answering that single question, and Chapter 9 described a few circumstances in which satisfactory answers to that question do not exist. This chapter takes the performance problem out of that self-imposed box and considers how to solve the rare query runtime problems that cannot be solved just by tuning a given statement.