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[数据库]初涉SQL Server性能问题(3/4):列出阻塞的会话


在 初涉SQL Server性能问题(2/4)里,我们讨论了列出等待资源或正运行的会话脚本。这篇文章我们会看看如何列出包含具体信息的话阻塞会话清单。

 1 /******************************************************************************************/ 2 CREATE FUNCTION [dbo].dba_GetStatementForSpid 3 (  4  @spid SMALLINT  5 )  6 RETURNS NVARCHAR(4000)  7 BEGIN  8  DECLARE @SqlHandle BINARY(20)  9  DECLARE @SqlText NVARCHAR(4000) 10  SELECT @SqlHandle = sql_handle  11    FROM sys.sysprocesses WITH (nolock) WHERE  spid = @spid 12  SELECT @SqlText = [text] FROM  13    sys.dm_exec_sql_text(@SqlHandle) 14  RETURN @SqlText 15 END 16 GO17 18 /*****************************************************************************************19 STEP 4: List the current blocking session information20 ****************************************************************************************/21 22 SELECT23 es.session_id,24 es.HOST_NAME,25 DB_NAME(database_id) AS DatabaseName, 26 CASE WHEN es.program_name LIKE '%SQLAgent - TSQL JobStep%' THEN (SELECT 'SQL AGENT JOB: '+name FROM msdb..sysjobs WHERE job_id=MASTER.DBO.ConvertStringToBinary (LTRIM(RTRIM((SUBSTRING(es.program_name,CHARINDEX('(job',es.program_name,0)+4,35)))))) 27 ELSE es.program_name END AS program_name ,28 es.login_name ,29 bes.session_id AS Blocking_session_id,30 MASTER.DBO.dba_GetStatementForSpid(es.session_id) AS [Statement],31 bes.HOST_NAME AS Blocking_hostname,32 CASE WHEN Bes.program_name LIKE '%SQLAgent - TSQL JobStep%' THEN33 (SELECT 'SQL AGENT JOB: '+name FROM msdb..sysjobs WHERE job_id=34 MASTER.DBO.ConvertStringToBinary 35 (LTRIM(RTRIM((SUBSTRING(Bes.program_name,CHARINDEX('(job',es.program_name,0)+4,35))))))36 ELSE Bes.program_name END AS Blocking_program_name,37 bes.login_name AS Blocking_login_name,38  MASTER.DBO.dba_GetStatementForSpid(bes.session_id ) AS [Blocking Statement]39 FROM sys.dm_exec_requests S 40 INNER JOIN sys.dm_exec_sessions es ON es.session_id=s.session_id41 INNER JOIN sys.dm_exec_sessions bes ON bes.session_id=s.blocking_session_id

这个脚本会列出被阻塞和正阻塞的语句信息,帮助我们进行问题分析。下面的脚本会帮助我们列出已经打开事务但未活动的会话,即打开事务,但上30秒内都没执行任何语句的会话。

 1 /***************************************************************************************** 2 STEP 4: List the Open session with transaction which is not active 3 ****************************************************************************************/ 4 SELECT es.session_id,  5 es.login_name,  6 es.HOST_NAME,  7 DB_NAME(SP.dbid) AS DatabaseName, 8 sp.lastwaittype, 9 est.TEXT,cn.last_read, 10 cn.last_write, 11 CASE WHEN es.program_name LIKE '%SQLAgent - TSQL JobStep%' THEN(SELECT 'SQL AGENT JOB: '+name FROM msdb..sysjobs WHERE job_id=MASTER.DBO.ConvertStringToBinary (LTRIM(RTRIM((SUBSTRING(es.program_name,CHARINDEX('(job',es.program_name,0)+4,35)))))12 )ELSE es.program_name END AS program_name 13 FROM sys.dm_exec_sessions es14 INNER JOIN sys.dm_tran_session_transactions st ON es.session_id = st.session_id        INNER JOIN sys.dm_exec_connections cn ON es.session_id = cn.session_id 15 INNER JOIN sys.sysprocesses SP ON SP.spid=es.session_id         16 LEFT OUTER JOIN sys.dm_exec_requests er ON st.session_id = er.session_id  17 AND er.session_id IS NULL       18 CROSS APPLY sys.dm_exec_sql_text(cn.most_recent_sql_handle) est        19 WHERE (DATEDIFF(SS,cn.last_read,GETDATE())+DATEDIFF(SS,cn.last_write,GETDATE()))>3020 AND lastwaittype NOT IN ('BROKER_RECEIVE_WAITFOR' ,'WAITFOR')                 21 GO