---查看当前数据库系统所有请求情况.我只列出了我认为比较重要有助于我解决问题的字段。

SELECT ds.session_id,

       ds.status,

       Db_name(dr.database_id) AS database_name,

       ds.login_name,

       ds.login_time,

       ds.host_name,

       dc.client_net_address,

       dc.client_tcp_port,

       ds.program_name,

       dr.cpu_time,

       dr.reads,

       dr.writes,

       dc.num_reads,

       dc.num_writes,

       ds.client_interface_name,

       ds.last_request_start_time,

       ds.last_request_end_time,

       dc.connect_time,

       dc.net_transport,

       dc.net_packet_size,

       dr.start_time,

       dr.status,

       dr.command,

       dr.blocking_session_id,

       dr.wait_type,

       dr.wait_time,

       dr.last_wait_type,

       dr.wait_resource,

       dr.open_transaction_count,

       dr.percent_complete,

       dr.granted_query_memory

FROM   Sys.dm_exec_requests dr WITH(nolock)

       RIGHT OUTER JOIN Sys.dm_exec_sessions ds WITH(nolock)

                     ON dr.session_id = ds.session_id

       RIGHT OUTER JOIN Sys.dm_exec_connections dc WITH(nolock)

                     ON ds.session_id = dc.session_id

WHERE  ds.session_id > 50

ORDER  BY ds.program_name

----用户连接数

SELECT login_name,

       Count(0) user_count

FROM   Sys.dm_exec_requests dr WITH(nolock)

       RIGHT OUTER JOIN Sys.dm_exec_sessions ds WITH(nolock)

                     ON dr.session_id = ds.session_id

       RIGHT OUTER JOIN Sys.dm_exec_connections dc WITH(nolock)

                     ON ds.session_id = dc.session_id

WHERE  ds.session_id > 50

GROUP  BY login_name

ORDER  BY user_count DESC