Pages and Extents Architecture

The page is the fundamental unit of data storage in SQL Server. An extent is a collection of eight physically contiguous pages. Extents help efficiently manage pages.

This section describes the data structures that are used to manage pages and extents. Understanding the architecture of pages and extents is important for designing and developing databases that perform efficiently.

In This Section

• Understanding Pages and Extents
  Describes how data is stored in pages and extents.

• Managing Extent Allocations and Free Space
  Describes the SQL Server data structures that manage extent allocations and track free space.

• Managing Space Used by Objects
  Describes how space is allocated for objects.

• Tracking Modified Extents
  Describes internal data structures that help track extents modified by bulk copy operations and extents modified since the last full backup.