--所有请求情况：
SELECT s.session_id ,
s.status ,
DB_NAME(r.database_id) AS database_name ,
s.login_name ,
s.login_time ,
s.host_name ,
c.client_net_address ,
c.client_tcp_port ,
s.program_name ,
r.cpu_time ,
r.reads ,
r.writes ,
c.num_reads ,
c.num_writes ,
s.client_interface_name ,
s.last_request_start_time ,
s.last_request_end_time ,
c.connect_time ,
c.net_transport ,
c.net_packet_size ,
r.start_time ,
r.status ,
r.command ,
r.blocking_session_id ,
r.wait_type ,
r.wait_time ,
r.last_wait_type ,
r.wait_resource ,
r.open_transaction_count ,
r.percent_complete ,
r.granted_query_memory
FROM Sys.dm_exec_requests r WITH ( NOLOCK )
RIGHT OUTER JOIN Sys.dm_exec_sessions s WITH ( NOLOCK ) ON r.session_id = s.session_id
RIGHT OUTER JOIN Sys.dm_exec_connections c WITH ( NOLOCK ) ON s.session_id = c.session_id
WHERE 1 = 1
AND s.session_id > 50
ORDER BY s.session_id
-- 哪个用户连接数最多：
SELECT login_name ,
COUNT(0) user_count
FROM Sys.dm_exec_requests r WITH ( NOLOCK )
RIGHT OUTER JOIN Sys.dm_exec_sessions s WITH ( NOLOCK ) ON r.session_id = s.session_id
RIGHT OUTER JOIN Sys.dm_exec_connections c WITH ( NOLOCK ) ON s.session_id = c.session_id
WHERE s.session_id > 50
GROUP BY login_name
ORDER BY 2 DESC
--哪台机器发起到数据库的连接数最多：
SELECT s.host_name ,
c.client_net_address ,
COUNT(0) host_count
FROM Sys.dm_exec_requests r WITH ( NOLOCK )
RIGHT OUTER JOIN Sys.dm_exec_sessions s WITH ( NOLOCK ) ON r.session_id = s.session_id
RIGHT OUTER JOIN Sys.dm_exec_connections c WITH ( NOLOCK ) ON s.session_id = c.session_id
WHERE s.session_id > 50
GROUP BY host_name ,
client_net_address
ORDER BY 3 DESC
-- 进程状态：
SELECT s.status ,
COUNT(0) host_count
FROM Sys.dm_exec_requests r WITH ( NOLOCK )
RIGHT OUTER JOIN Sys.dm_exec_sessions s WITH ( NOLOCK ) ON r.session_id = s.session_id
RIGHT OUTER JOIN Sys.dm_exec_connections c WITH ( NOLOCK ) ON s.session_id = c.session_id
WHERE s.session_id > 50
GROUP BY s.status
ORDER BY 2 DESC
--结果（running数比较多，表面数据库压力比较大）：