Microsoft SQL Server 2012 Internals

The scheduler

Prior to SQL Server 7.0, scheduling depended entirely on the underlying Windows operating system. Although this meant that SQL Server could take advantage of the hard work done by Windows engineers to enhance scalability and efficient processor use, definite limits existed. Because the Windows scheduler knew nothing about the needs of a relational database system, it treated SQL Server worker threads the same as any other process running on the operating system. However, a high-performance system such as SQL Server functions best when the scheduler can meet its special needs. SQL Server 7.0 and all subsequent versions are designed to handle their own scheduling to gain a number of advantages, including the following.

• A private scheduler ...