Space Allocation and Reuse

SQL Server 2005 is effective at quickly allocating pages to objects and reusing space that is made available by deleted rows. These operations are internal to the system and use data structures that are not visible to users. However, these processes and structures are still occasionally referenced in SQL Server messages.

This section is an overview of the space allocation algorithms and the data structures. It also provides users and administrators with the knowledge they require to understand the references to the terms in the messages generated by SQL Server.

In This Section

Topic Description

Managing Extent Allocations and Free Space

Explains how extents are allocated and managed in SQL Server and how free space in the database is managed.

Managing Space Used by Objects

Explains how database objects in the database are mapped to pages and extents.

Tracking Modified Extents

Describes the Differential Changed Map (DCM) and Bulk Changed Map (BCM) structures used to track modified extents.

See Also


Pages and Extents

Other Resources

Physical Database Architecture

Help and Information

Getting SQL Server 2005 Assistance