sys.dm_db_session_space_usage (Transact-SQL)
Applies to: 
SQL Server (all supported versions) Azure SQL DatabaseAzure SQL Managed InstanceAzure Synapse AnalyticsParallel Data Warehouse
Returns the number of pages allocated and deallocated by each session for the database.
Note
This view is applicable only to the tempdb database.
Note
To call this from Azure Synapse Analytics (SQL Data Warehouse) or Parallel Data Warehouse, use the name sys.dm_pdw_nodes_db_session_space_usage.
| 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. |
| user_objects_deferred_dealloc_page_count | bigint | Number of pages which have been marked for deferred deallocation. Note: Introduced in service packs for SQL Server 2012 (11.x) and SQL Server 2014 (12.x). |
| pdw_node_id | int | Applies to: Azure Synapse Analytics (SQL Data Warehouse), Parallel Data Warehouse The identifier for the node that this distribution is on. |
Permissions
On SQL Server, requires VIEW SERVER STATE permission.
On SQL Database Premium Tiers, requires the VIEW DATABASE STATE permission in the database. On SQL Database Standard and Basic Tiers, requires the Server admin or an Azure Active Directory admin account.
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
Relationship Cardinalities
| From | To | Relationship |
|---|---|---|
| dm_db_session_space_usage.session_id | dm_exec_sessions.session_id | One-to-one |
See Also
Dynamic Management Views and Functions (Transact-SQL)
Database Related Dynamic Management Views (Transact-SQL)
sys.dm_exec_sessions (Transact-SQL)
sys.dm_exec_requests (Transact-SQL)
sys.dm_os_tasks (Transact-SQL)
sys.dm_db_task_space_usage (Transact-SQL)
sys.dm_db_file_space_usage (Transact-SQL)