The Staged Event-Driven Architecture (SEDA) is a new design for building scalable Internet services. SEDA has three major goals:
To support massive concurrency, on the order of tens of thousands of clients per node
To exhibit robust performance under wide variations in load and,
To simplify the design of complex Internet services.
SEDA decomposes a complex, event-driven application into a set of stages connected by queues. This design avoids the high overhead associated with thread-based concurrency models, and decouples event and thread scheduling from application logic. SEDA enables services to be well-conditioned to load, preventing resources from being overcommitted when demand exceeds service capacity. Decomposing services into a set of stages also enables modularity and code reuse, as well as the development of debugging tools for complex event-driven applications.
SQL Server 2005 Integration Services (SSIS) is a new Extract, Transform, and Load (ETL) tool that ships with SQL Server 2005. As with many of Microsoft s development tools, you can extend SSIS to perform other operations not already bundled with the product. SSIS provides the SSIS Class Library for just this purpose. The SSIS Class Library Object Model includes all the classes and interfaces you need to extend or augment SSIS.
SQL Server developers and administrators are no strangers to Data Transformation Services (DTS) packages. They likely develop DTS packages to perform everything from simple database operations to data aggregation. As such, when they upgrade some or all of their servers to SQL Server 2005, they must decide what to do with all of their DTS packages
The initial planning and thinking about this book began during a discussion of SQL Server futures in
July 2001. The discussion was with Rob Howard during a trip to Microsoft to discuss the first book I was
working on at that time. After that, I stayed involved in what was happening in ADO.NET by going to
the SQL Server Yukon Technical Preview in Bellevue, Washington, in February 2002 and by working
with the ASP.NET and SQL Server teams at Microsoft since July 2003.