标签:dm exec 30 视图 Server sys session id Blocked
SQL Server通过动态视图里查找阻塞的会话
简介
对于阻塞我们可以通过动态视图dm_exec_requests、dm_tran_locks等关联通过构建递归式树形结构来查找出阻塞超过30秒的会话。
阻塞查询
WITH Blocked_Sessions AS (
-- 找到所有阻塞的会话
SELECT sys.dm_exec_requests.blocking_session_id AS lead_session_id,
sys.dm_exec_requests.blocking_session_id AS blocking_session_id , 0 Cnt
FROM sys.dm_exec_requests
WHERE blocking_session_id <> 0
AND blocking_session_id NOT IN (SELECT session_id
FROM sys.dm_exec_requests
WHERE sys.dm_exec_requests.blocking_session_id <> 0)
UNION ALL
-- 遍历所有的会话(构建树型关系)
SELECT Blocked_Sessions.lead_session_id, sys.dm_exec_requests.session_id, 1 Cnt
FROM sys.dm_exec_requests
JOIN Blocked_Sessions
ON Blocked_Sessions.blocking_session_id = sys.dm_exec_requests.blocking_session_id
),
Blocked AS (
SELECT lead_session_id, SUM(Cnt) AS sessions_blocked
FROM Blocked_Sessions
GROUP BY lead_session_id)
SELECT Blocked.*, DATEDIFF(s, Sess.last_request_start_time, getdate()) seconds_blocking,
ISNULL(Req.status,'sleeping') [status], SqlText.text [sql_text],
STUFF((SELECT DISTINCT ISNULL(', ' + db.name,'')
FROM sys.databases db
JOIN sys.dm_tran_locks lcks
ON db.database_id = lcks.resource_database_id
WHERE lcks.request_session_id = Sess.session_id
ORDER BY ISNULL(', ' + db.name,'')
FOR XML PATH(''),TYPE).value('.','VARCHAR(MAX)')
,1,2,'') AS database_list
, Conn.client_net_address, Sess.login_name
FROM sys.dm_exec_connections Conn
LEFT OUTER JOIN sys.dm_exec_sessions Sess
ON Conn.session_id = Sess.session_id
JOIN Blocked
ON Blocked.lead_session_id = Sess.session_id
CROSS APPLY sys.dm_exec_sql_text(Conn.most_recent_sql_handle) SqlText
LEFT JOIN sys.dm_exec_requests Req
ON Req.session_id = Sess.session_id
WHERE Blocked.sessions_blocked >= 1
-- 过滤阻塞超过30秒的记录
AND DATEDIFF(s, Sess.last_request_start_time, getdate()) > 30;
标签:dm,exec,30,视图,Server,sys,session,id,Blocked 来源: https://blog.csdn.net/shenliang1985/article/details/119415140
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