Data Structures, Indexes, and Their Application

Abstract

To me, the true beauty of the relational database engine comes from its declarative nature. As a programmer, I simply ask the engine a question, and it answers it. The questions I ask are usually pretty simple; just give me some data from a few tables, correlate it based on a column or two, do a little math perhaps, and give me back information (and naturally do it incredibly fast, if you don’t mind, regardless of the fact that there are 10 billion rows involved). While simple may not actually be the right single-word description for what I have asked, the engine usually obliges with an answer pretty quickly. Usually, but not always. This is where the DBA and data programmers must figure out what the optimizer is doing and help it along.