[转帖]sys.dm_exec_connections (Transact-SQL)

Posted 2022-10-01 jinanxiaolaohu

sys.dm_exec_connections (Transact-SQL)

https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-exec-connections-transact-sql?view=sql-server-2017

 

APPLIES TO: SQL Server Azure SQL Database Azure SQL Data Warehouse Parallel Data Warehouse

Returns information about the connections established to this instance of SQL Server and the details of each connection. Returns server wide connection information for SQL Server. Returns current database connection information for SQL Database.

 Note

To call this from Azure SQL Data Warehouse or Parallel Data Warehouse, use sys.dm_pdw_exec_connections (Transact-SQL).

Column name	Data type	Description
session_id	int	Identifies the session associated with this connection. Is nullable.
most_recent_session_id	int	Represents the session ID for the most recent request associated with this connection. (SOAP connections can be reused by another session.) Is nullable.
connect_time	datetime	Timestamp when connection was established. Is not nullable.
net_transport	nvarchar(40)	Always returns Session when a connection has multiple active result sets (MARS) enabled. Note: Describes the physical transport protocol that is used by this connection. Is not nullable.
protocol_type	nvarchar(40)	Specifies the protocol type of the payload. It currently distinguishes between TDS (TSQL) and SOAP. Is nullable.
protocol_version	int	Version of the data access protocol associated with this connection. Is nullable.
endpoint_id	int	An identifier that describes what type of connection it is. This endpoint_id can be used to query the sys.endpoints view. Is nullable.
encrypt_option	nvarchar(40)	Boolean value to describe whether encryption is enabled for this connection. Is not nullable.
auth_scheme	nvarchar(40)	Specifies SQL Server/Windows Authentication scheme used with this connection. Is not nullable.
node_affinity	smallint	Identifies the memory node to which this connection has affinity. Is not nullable.
num_reads	int	Number of byte reads that have occurred over this connection. Is nullable.
num_writes	int	Number of byte writes that have occurred over this connection. Is nullable.
last_read	datetime	Timestamp when last read occurred over this connection. Is nullable.
last_write	datetime	Timestamp when last write occurred over this connection. Not Is nullable.
net_packet_size	int	Network packet size used for information and data transfer. Is nullable.
client_net_address	varchar(48)	Host address of the client connecting to this server. Is nullable. Prior to V12 in Azure SQL Database, this column always returns NULL.
client_tcp_port	int	Port number on the client computer that is associated with this connection. Is nullable. In Azure SQL Database, this column always returns NULL.
local_net_address	varchar(48)	Represents the IP address on the server that this connection targeted. Available only for connections using the TCP transport provider. Is nullable. In Azure SQL Database, this column always returns NULL.
local_tcp_port	int	Represents the server TCP port that this connection targeted if it were a connection using the TCP transport. Is nullable. In Azure SQL Database, this column always returns NULL.
connection_id	uniqueidentifier	Identifies each connection uniquely. Is not nullable.
parent_connection_id	uniqueidentifier	Identifies the primary connection that the MARS session is using. Is nullable.
most_recent_sql_handle	varbinary(64)	The SQL handle of the last request executed on this connection. The most_recent_sql_handle column is always in sync with the most_recent_session_id column. Is nullable.
pdw_node_id	int	Applies to: Azure 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.

Physical Joins

Relationship Cardinalities

dm_exec_sessions.session_id	dm_exec_connections.session_id	One-to-one
dm_exec_requests.connection_id	dm_exec_connections.connection_id	Many to one
dm_broker_connections.connection_id	dm_exec_connections.connection_id	One to one

Examples

Typical query to gather information about a queries own connection.

SQLCopy

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;  

See Also

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