---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_memoryFROM   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_idWHERE  ds.session_id > 50ORDER  BY ds.program_name----用户连接数SELECT login_name,       Count(0) user_countFROM   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_idWHERE  ds.session_id > 50GROUP  BY login_nameORDER  BY user_count DESC