I get a lot of nice feedback about my columns and classes, but some people ask me why they should bother learning how SQL Server works. I study internals often just for a deeper understanding of my favorite software and for the experience of learning something new. But many of my readers and students have specific reasons for learning about SQL Server internals. One of the most common reasons is that once you understand the way SQL Server works, you're better prepared to track down problems. If you understand the way indexes work, for example, you know that a query that takes 5 seconds to return 1 row, even from a 10 million­row table, can probably be improved.

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