IN THIS CHAPTER
SQL Server 2005 is loaded with features related to scalability, reliability, performance, high availability, programmability, security, and manageability. These features and enhancements are the primary drivers for the major overhauls in several areas of the database engine to accommodate a seamless integration throughout. Microsoft has made changes to SQL Server's memory management, thread scheduling, statistics management, parallelism, system metadata management, query optimization and execution, transactions, and other areas to better support new hardware architectures.
SQL Server has a single code base that can scale a small application that supports a few users to a large and complex enterprise application that supports multi-terabyte databases and thousands of concurrent users. While the foundation for the architecture that can achieve such linear scalability was laid in SQL Server 7.0 and further enhanced in SQL Server 2000, SQL Server 2005 offers significant changes and enhancements, taking SQL Server further into mission-critical enterprise database space.
This chapter provides an overview of the architectural changes made to the SQL Server 2005 database engine. If you are interested only in the functional operations of SQL Server 2005 and want to consider engine behavior as a black box operation, you can safely skip this chapter. If you want to first understand new features and enhancements introduced in this release, you can come back to this chapter after you have become more familiar with SQL Server 2005's functionality. This chapter covers the relational database engine architecture details only. Systems such as Analysis Services, Reporting Services, SQL Server Integration Services (formerly known as Data Transformation Services), and Notification Services have their own architectural enhancements, which are beyond the scope of this chapter.