Foreword

This is the seminal architectural description of SQL Server's database engine. Kalen Delaney's previous book, describing SQL Server 2000, is on my desk and the desks of most SQL Server expertsused whenever one wants a concise description of how something works or the design rational for some aspect of the system. Indeed, most SQL Server architects and developers use Kalen's book as a reference. So, we have been pestering Kalen with the question: "When can I get the SQL Server 2005 book?"

Having just finished reading the galleys, I understand why the book took so long. This is not a revision of the previous book. So much has changed and there are so many new features that Kalen had to write a brand new book. She worked closely with the architects to understand the new designs, and then she had to explain the designs in her concise and precise style. The result is well worth the wait. The book is encyclopedic. I watched the development of SQL Server 2005 from the inside, sometimes participating in design discussions; still, it is a very large system so there are many aspects that I did not understand. In reading the galleys, I learned a lot. I will be regularly re-reading sections in the years to come to refresh my understanding.

This book explains how the system works and gives you a deep understanding of what the designers intendedfor example diving deep into page formats, explaining allocation strategies, explaining the difference between temp tables and table variables, explaining how snapshot isolation works, explaining recovery options, explaining catalog views, explaining isolation levels and how they are implemented, and so on. The presentation is deep, concise, and yet very accessible and understandable. Along the way, the book gives sage advice on application design, database design, physical data layout, and performance tuning.

To put this book in perspective, SQL Server Books Online describes what exists; many books describe how to use those features; this book describes the design principles behind the database engine features and how they work. When you understand the principles and mechanisms, you can often infer what will work well and what will be problematic. So I heartily recommend this book to anyone who wants to design, implement, or manage systems involving SQL Server 2005.

Jim Gray

Technical Fellow, Microsoft Research

1999 ACM Turing Award Winner