最近公司的数据库并发有点大,由于CPU不高、内存不高、硬盘正常、网络也正常等等,但系统还是会卡,所以就怀疑是数据库阻塞导致的,于是去查询资料,看书及经过用以下sql观查,经过几天对数据的分析找到原因并解决后,在这里分享下。
一、准备知识
需要了解数据阻塞的基本知识,了解数据库常见锁的运行机制,有了这个基础后,对下面的sql执行的结果可以更加的了解,在使用以下sql时,准备这些知识是很重要的。
二、查看当前阻塞
运行 sp_lock 或
select spid,blocked,cmd,waittime,lastwaittype,waittype,waitresource,dbid,uid,cpu,physical_io,memusage,login_time,last_batch, open_tran,status,hostname,PRogram_name,net_library,loginame from sysprocesses where blocked>0
三、查看数据库当前锁的情况
select request_session_id,resource_type,resource_associated_entity_id,request_status,request_mode,resource_description,p.object_id,object_name(P.OBJECT_ID) as object_name,p.*from sys.dm_tran_locks left join sys.partitions p on sys.dm_tran_locks.resource_associated_entity_id=p.hobt_idwhere resource_database_id=db_id('数据库名')order by request_session_id,resource_type,resource_associated_entity_id
四、捕获数据库阻塞情况,将以下代码保存成sql文本件
/* sqlcmd -E -S . -i 捕获数据库阻塞情况.sql -w2000 -o log.out*/use mastergo while 1=1begin print 'Start time:'+convert(varchar(26),getdate(),121) print 'Running processes' select spid,blocked,waittype,waittime,lastwaittype,waitresource,dbid,uid,cpu,physical_io,memusage,login_time,last_batch, open_tran,status,hostname,program_name,cmd,net_library,loginame from sysprocesses --where(ipid<>0) or(spid<51) --Change it if you only want to see the working processes print '*****lockinfo*****' select convert(smallint,req_spid) as spid, rsc_dbid as dbid, rsc_objid as objid, rsc_indid as indid, substring(v.name,1,4) as type, substring(rsc_text,1,16) as resource, substring(u.name,1,8) as mode, substring(x.name,1,5) as status from master.dbo.syslockinfo, master.dbo.spt_values v, master.dbo.spt_values x, master.dbo.spt_values u where master.dbo.syslockinfo.rsc_type=v.number and v.type='LR' and master.dbo.syslockinfo.req_status=x.number and x.type='LS' and master.dbo.syslockinfo.req_mode+1=u.number and u.type='L' order by spid print 'inputbuffer for running processes' declare @spid varchar(6) declare ibuffer cursor fast_forward for select cast(spid as varchar(6)) as spid from sysprocesses where spid>50 open ibuffer fetch next from ibuffer into @spid while (@@FETCH_STATUS!=-1) begin print '' print 'DBCC inputbuffer for spid '+@spid exec ('dbcc inputbuffer('+@spid+')') fetch next from ibuffer into @spid end deallocate ibuffer waitfor delay '0:0:10'end
代码每隔10秒运行一次。
在cmd里运行以下命令,会在当前目录里产生一个log.out,可能用editplus查看此日志,日志对锁的申请和占用都有详细的记录,可以量大的话可以每天重新运行。
sqlcmd -E -S . -i 捕获数据库阻塞情况.sql -w2000 -o log.out
PS:以上的代码大多都由《SQL Server 2012 实施与管理实战指南》上来的,还是非常实用的,这本书买了有一段时间,碰到问题了就起来来翻翻。
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