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sp_who (Transact-SQL)

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Applies to: SQL Server

Provides information about current users, sessions, and processes in an instance of the SQL Server Database Engine. The information can be filtered to return only those processes that aren't idle, that belong to a specific user, or that belong to a specific session.

Transact-SQL syntax conventions

Syntax

sp_who [ [ @loginame = ] { 'login' | *session_id* | 'ACTIVE' } ]
[ ; ]

Arguments

[ @loginame = ] { 'login' | session_id | 'ACTIVE' }

Used to filter the result set.

  • login is sysname that identifies processes belonging to a particular login.

  • session_id is a session identification number belonging to the SQL Server instance. session_id is smallint.

  • ACTIVE excludes sessions that are waiting for the next command from the user.

If no value is provided, the procedure reports all sessions belonging to the instance.

Return code values

0 (success) or 1 (failure).

Result set

sp_who returns a result set with the following information.

Column Data type Description
spid smallint Session ID.
ecid smallint Execution context ID of a given thread associated with a specific session ID.

ECID = { 0, 1, 2, 3, ...n }, where 0 always represents the main or parent thread, and { 1, 2, 3, ...n } represent the subthreads.
status nchar(30) Process status. The possible values are:

- dormant. SQL Server is resetting the session.

- running. The session is running one or more batches. When Multiple Active Result Sets (MARS) is enabled, a session can run multiple batches. For more information, see Using Multiple Active Result Sets (MARS).

- background. The session is running a background task, such as deadlock detection.

- rollback. The session has a transaction rollback in process.

- pending. The session is waiting for a worker thread to become available.

- runnable. The session's task is in the runnable queue of a scheduler while waiting to get a time quantum.

- spinloop. The session's task is waiting for a spinlock to become free.

- suspended. The session is waiting for an event, such as I/O, to complete.
loginame nchar(128) Login name associated with the particular process.
hostname nchar(128) Host or computer name for each process.
blk char(5) Session ID for the blocking process, if one exists. Otherwise, this column is 0.

When a transaction associated with a specified session ID is blocked by an orphaned distributed transaction, this column returns a -2 for the blocking orphaned transaction.
dbname nchar(128) Database used by the process.
cmd nchar(16) Database Engine command (Transact-SQL statement, internal Database Engine process, and so on) executing for the process. In SQL Server 2019 (15.x) and later versions, the data type is nchar(26).
request_id int ID for requests running in a specific session.

With parallel processing, subthreads are created for the specific session ID. The main thread is indicated as spid = <xxx> and ecid = 0. The other subthreads have the same spid = <xxx>, but with ecid > 0.

Remarks

A blocking process, which might have an exclusive lock, is one that is holding resources that another process needs.

All orphaned distributed transactions are assigned the session ID value of -2. Orphaned distributed transactions are distributed transactions that aren't associated with any session ID. For more information, see Use Marked Transactions to Recover Related Databases Consistently.

Query the is_user_process column of sys.dm_exec_sessions to separate system processes from user processes.

Permissions

Requires VIEW SERVER STATE permission on the server to see all executing sessions on the instance of SQL Server. Otherwise, the user sees only the current session.

Examples

A. List all current processes

The following example uses sp_who without parameters to report all current users.

USE master;
GO
EXEC sp_who;
GO

B. List a specific user's process

The following example shows how to view information about a single current user by login name.

USE master;
GO
EXEC sp_who 'janetl';
GO

C. Display all active processes

USE master;
GO
EXEC sp_who 'active';
GO

D. Display a specific process identified by a session ID

USE master;
GO
EXEC sp_who '10' --specifies the process_id;
GO

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