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sys.dm_db_session_space_usage (Transact-SQL)

Returns the number of pages allocated and deallocated by each session for the database.

Note

This view is applicable only to thetempdb database.

Column name

Data type

Description

session_id

smallint

Session ID.

session_id maps to session_id in sys.dm_exec_sessions.

database_id

smallint

Database ID.

user_objects_alloc_page_count

bigint

Number of pages reserved or allocated for user objects by this session.

user_objects_dealloc_page_count

bigint

Number of pages deallocated and no longer reserved for user objects by this session.

internal_objects_alloc_page_count

bigint

Number of pages reserved or allocated for internal objects by this session.

internal_objects_dealloc_page_count

bigint

Number of pages deallocated and no longer reserved for internal objects by this session.

Permissions

Requires VIEW SERVER STATE permission on the server.

Remarks

IAM pages are not included in any of the allocation or deallocation counts reported by this view.

Page counters are initialized to zero (0) at the start of a session. The counters track the total number of pages that have been allocated or deallocated for tasks that are already completed in the session. The counters are updated only when a task ends; they do not reflect running tasks.

A session can have multiple requests active at the same time. A request can start multiple threads, tasks, if it is a parallel query.

For more information about the sessions, requests, and tasks, see sys.dm_exec_sessions (Transact-SQL), sys.dm_exec_requests (Transact-SQL), and sys.dm_os_tasks (Transact-SQL).

User Objects

The following objects are included in the user object page counters:

  • User-defined tables and indexes

  • System tables and indexes

  • Global temporary tables and indexes

  • Local temporary tables and indexes

  • Table variables

  • Tables returned in the table-valued functions

Internal Objects

Internal objects are only in tempdb. The following objects are included in the internal object page counters:

  • Work tables for cursor or spool operations and temporary large object (LOB) storage

  • Work files for operations such as a hash join

  • Sort runs

Physical Joins

Physical joins for sys.dm_db_session_space_usage

Relationship Cardinalities

From

To

Relationship

dm_db_session_space_usage.session_id

dm_exec_sessions.session_id

One-to-one

Examples

For examples that use the sys.dm_db_session_space_usage view, see Troubleshooting Insufficient Disk Space in tempdb.