sys.dm_exec_sessions (Transact-SQL)

Returns one row per authenticated session on SQL Server. sys.dm_exec_sessions is a server-scope view that shows information about all active user connections and internal tasks. This information includes client version, client program name, client login time, login user, current session setting, and more. Use sys.dm_exec_sessions to first view the current system load and to identify a session of interest, and then learn more information about that session by using other dynamic management views or dynamic management functions.

The sys.dm_exec_connections, sys.dm_exec_sessions, and sys.dm_exec_requests dynamic management views map to the sys.sysprocesses system table.

Column name	Data type	Description
session_id	smallint	Identifies the session associated with each active primary connection. Is not nullable.
login_time	datetime	Time when session was established. Is not nullable.
host_name	nvarchar(128)	Name of the client workstation that is specific to a session. The value is NULL for internal sessions. Is nullable. Uwaga dotycząca zabezpieczeń The client application provides the workstation name and can provide inaccurate data. Do not rely upon HOST_NAME as a security feature.
program_name	nvarchar(128)	Name of client program that initiated the session. The value is NULL for internal sessions. Is nullable.
host_process_id	int	Process ID of the client program that initiated the session. The value is NULL for internal sessions. Is nullable.
client_version	int	TDS protocol version of the interface that is used by the client to connect to the server. The value is NULL for internal sessions. Is nullable.
client_interface_name	nvarchar(32)	Protocol name that is used by the client to connect to the server. The value is NULL for internal sessions. Is nullable.
security_id	varbinary(85)	Microsoft Windows security ID associated with the login. Is not nullable.
login_name	nvarchar(128)	SQL Server login name under which the session is currently executing. For the original login name that created the session, see original_login_name. Can be a SQL Server authenticated login name or a Windows authenticated domain user name. Is not nullable.
nt_domain	nvarchar(128)	Windows domain for the client if the session is using Windows Authentication or a trusted connection. This value is NULL for internal sessions and non-domain users. Is nullable.
nt_user_name	nvarchar(128)	Windows user name for the client if the session is using Windows Authentication or a trusted connection. This value is NULL for internal sessions and non-domain users. Is nullable.
status	nvarchar(30)	Status of the session. Possible values: Running - Currently running one or more requests Sleeping - Currently running no requests Dormant – Session has been reset because of connection pooling and is now in prelogin state. Preconnect - Session is in the Resource Governor classifier. Is not nullable.
context_info	varbinary(128)	CONTEXT_INFO value for the session. The context information is set by the user by using the SET CONTEXT_INFO statement. Is nullable.
cpu_time	int	CPU time, in milliseconds, that was used by this session. Is not nullable.
memory_usage	int	Number of 8-KB pages of memory used by this session. Is not nullable.
total_scheduled_time	int	Total time, in milliseconds, for which the session (requests within) were scheduled for execution. Is not nullable.
total_elapsed_time	int	Time, in milliseconds, since the session was established. Is not nullable.
endpoint_id	int	ID of the Endpoint associated with the session. Is not nullable.
last_request_start_time	datetime	Time at which the last request on the session began. This includes the currently executing request. Is not nullable.
last_request_end_time	datetime	Time of the last completion of a request on the session. Is nullable.
reads	bigint	Number of reads performed, by requests in this session, during this session. Is not nullable.
writes	bigint	Number of writes performed, by requests in this session, during this session. Is not nullable.
logical_reads	bigint	Number of logical reads that have been performed on the session. Is not nullable.
is_user_process	bit	0 if the session is a system session. Otherwise, it is 1. Is not nullable.
text_size	int	TEXTSIZE setting for the session. Is not nullable.
language	nvarchar(128)	LANGUAGE setting for the session. Is nullable.
date_format	nvarchar(3)	DATEFORMAT setting for the session. Is nullable.
date_first	smallint	DATEFIRST setting for the session. Is not nullable.
quoted_identifier	bit	QUOTED_IDENTIFIER setting for the session. Is not nullable.
arithabort	bit	ARITHABORT setting for the session. Is not nullable.
ansi_null_dflt_on	bit	ANSI_NULL_DFLT_ON setting for the session. Is not nullable.
ansi_defaults	bit	ANSI_DEFAULTS setting for the session. Is not nullable.
ansi_warnings	bit	ANSI_WARNINGS setting for the session. Is not nullable.
ansi_padding	bit	ANSI_PADDING setting for the session. Is not nullable.
ansi_nulls	bit	ANSI_NULLS setting for the session. Is not nullable.
concat_null_yields_null	bit	CONCAT_NULL_YIELDS_NULL setting for the session. Is not nullable.
transaction_isolation_level	smallint	Transaction isolation level of the session. 0 = Unspecified 1 = ReadUncomitted 2 = ReadCommitted 3 = Repeatable 4 = Serializable 5 = Snapshot Is not nullable.
lock_timeout	int	LOCK_TIMEOUT setting for the session. The value is in milliseconds. Is not nullable.
deadlock_priority	int	DEADLOCK_PRIORITY setting for the session. Is not nullable.
row_count	bigint	Number of rows returned on the session up to this point. Is not nullable.
prev_error	int	ID of the last error returned on the session. Is not nullable.
original_security_id	varbinary(85)	Microsoft Windows security ID that is associated with the original_login_name. Is not nullable.
original_login_name	nvarchar(128)	SQL Server login name that the client used to create this session. Can be a SQL Server authenticated login name, a Windows authenticated domain user name, or a contained database user. Note that the session could have gone through many implicit or explicit context switches after the initial connection. For example, if EXECUTE AS is used. Is not nullable.
last_successful_logon	datetime	Time of the last successful logon for the original_login_name before the current session started.
last_unsuccessful_logon	datetime	Time of the last unsuccessful logon attempt for the original_login_name before the current session started.
unsuccessful_logons	bigint	Number of unsuccessful logon attempts for the original_login_name between the last_successful_logon and login_time.
group_id	int	ID of the workload group to which this session belongs. Is not nullable.
database_id	smallint	ID of the current database for each session.
authenticating_database_id	int	ID of the database authenticating the principal. For Logins, the value will be 0. For contained database users, the value will be the database ID of the contained database.
open_transaction_count	int	Number of open transactions per session.

Permissions

Requires VIEW SERVER STATE permission on server.

[!UWAGA]

If the user has VIEW SERVER STATE permission on the server, the user will see all executing sessions on the instance of SQL Server; otherwise, the user will see only the current session.

Uwagi

When the common criteria compliance enabled server configuration option is enabled, logon statistics are displayed in the following columns.

• last_successful_logon

• last_unsuccessful_logon

• unsuccessful_logons

If this option is not enabled, these columns will return null values. For more information about how to set this server configuration option, see common criteria compliance enabled Server Configuration Option.

Relationship Cardinalities

From	To	On/Apply	Relationship
sys.dm_exec_sessions	sys.dm_exec_requests	session_id	One-to-zero or one-to-many
sys.dm_exec_sessions	sys.dm_exec_connections	session_id	One-to-zero or one-to-many
sys.dm_exec_sessions	sys.dm_tran_session_transactions	session_id	One-to-zero or one-to-many
sys.dm_exec_sessions	sys.dm_exec_cursors(session_id | 0)	session_id CROSS APPLY OUTER APPLY	One-to-zero or one-to-many
sys.dm_exec_sessions	sys.dm_db_session_space_usage	session_id	One-to-one

Examples

A. Finding users that are connected to the server

The following example finds the users that are connected to the server and returns the number of sessions for each user.

SELECT login_name ,COUNT(session_id) AS session_count 
FROM sys.dm_exec_sessions 
GROUP BY login_name;

B. Finding long-running cursors

The following example finds the cursors that have been open for more than a specific period of time, who created the cursors, and what session the cursors are on.

USE master;
GO
SELECT creation_time ,cursor_id 
    ,name ,c.session_id ,login_name 
FROM sys.dm_exec_cursors(0) AS c 
JOIN sys.dm_exec_sessions AS s 
   ON c.session_id = s.session_id 
WHERE DATEDIFF(mi, c.creation_time, GETDATE()) > 5;

C. Finding idle sessions that have open transactions

The following example finds sessions that have open transactions and are idle. An idle session is one that has no request currently running.

SELECT s.* 
FROM sys.dm_exec_sessions AS s
WHERE EXISTS 
    (
    SELECT * 
    FROM sys.dm_tran_session_transactions AS t
    WHERE t.session_id = s.session_id
    )
    AND NOT EXISTS 
    (
    SELECT * 
    FROM sys.dm_exec_requests AS r
    WHERE r.session_id = s.session_id
    );

D. Finding information about a queries own connection

Typical query to gather information about a queries own connection.

SELECT 
    c.session_id, c.net_transport, c.encrypt_option, 
    c.auth_scheme, s.host_name, s.program_name, 
    s.client_interface_name, s.login_name, s.nt_domain, 
    s.nt_user_name, s.original_login_name, c.connect_time, 
    s.login_time 
FROM sys.dm_exec_connections AS c
JOIN sys.dm_exec_sessions AS s
    ON c.session_id = s.session_id
WHERE c.session_id = @@SPID;

Zobacz także

Odwołanie

Dynamic Management Views and Functions (Transact-SQL)

Execution Related Dynamic Management Views and Functions (Transact-SQL)