转载地址：https://www.cnblogs.com/tianqing/p/11152799.html
今天线上SQLServer数据库的CPU被打爆了，紧急情况下，分析了数据库阻塞、连接分布、最耗CPU的TOP10 SQL、查询SQL并行度配置、查询SQL 重编译的原因等等
整理了一些常用的SQL
1. 查询数据库阻塞
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SELECT * FROM sys.sysprocesses WHERE blocked<>0
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查询结果中，重点看Blocked这一列，先找出最多的SID，然后循环找出Root的阻塞根源SID
查询阻塞根源Session的SQL
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DBCC Inputbuffer(sid) |
2. 查询SQL连接分布
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SELECT Hostname FROM sys.sysprocesses WHERE hostname<>''
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1，查看连接到‘TestDB2’数据库的连接
select * from master.dbo.sysprocesses
where dbid = DB_ID('TestDB2')
*查询某个数据库用户的连接情况
sp_who 'sa'
2，查看数据库允许的最大连接
select @@MAX_CONNECTIONS
3，查看数据库自上次启动以来的连接次数
SELECT @@CONNECTIONS
4，关闭连接
上面的查询可以得到spid，根据spid，关闭进程就可以了。
kill 54
3. 查询最消耗CPU的SQL Top10
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select top(10) st.text as Query, qs.total_worker_time, qs.execution_count from
sys.dm_exec_query_stats as qs CROSS Apply sys.dm_exec_sql_text(qs.sql_handle) AS st
order by qs.total_worker_time desc
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4. 查看SQLServer并行度
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SELECT value_in_use FROM sys.configurations WHERE name = 'max degree of parallelism'
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并行度如果设置为1，To suppress parallel plan generation, set max degree of parallelism to 1
将阻止并行编译生成SQL执行计划，最大并行度设置为1
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USE DatabaseName ; GO EXEC sp_configure 'show advanced options', 1;
GO RECONFIGURE WITH OVERRIDE;
GO EXEC sp_configure 'max degree of parallelism', 16;
GO RECONFIGURE WITH OVERRIDE;
GO |
5. 查询SQL Server Recompilation Reasons
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select dxmv.name, dxmv.map_key,dxmv.map_value from
sys.dm_xe_map_values as dxmv where dxmv.name='statement_recompile_cause' order by dxmv.map_key
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6. 将SQL Trace文件存入一张表，做聚合分析（CPU、IO、执行时间等）
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SELECT * INTO TabSQL
FROM fn_trace_gettable('C:\Users\***\Desktop\Trace\sql05trace20180606-业务.trc', default);
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对上述表数据进行聚合分析最耗时的SQL
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select top 100
replace(replace(replace( substring(Textdata,1,6600) ,char(10),' '),char(13),' ') ,char(9),' ') as '名称',
--substring(Textdata,1,6600) as old,
count(*) as '数量',
sum(duration/1000) as '总执行时间ms',
avg(duration/1000) as '平均执行时间ms',
avg(cpu) as '平均CPU时间ms',
avg(reads) as '平均读次数',
avg(writes) as '平均写次数', LoginName
from TabSQL t
group by replace(replace(replace( substring(Textdata,1,6600) ,char(10),' '),char(13),' ') ,char(9),' ') , LoginName
order by sum(duration) desc
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最耗IO的SQL
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select TOP 100 replace(replace(replace( substring(Textdata,1,6600) ,char(10),' '),char(13),' ') ,char(9),' ') as '名称' ,LoginName,
count(*) as '数量',
sum(duration/1000) as '总执行时间ms',
avg(duration/1000) as '平均执行时间ms',
sum(cpu) as '总CPU时间ms',
avg(cpu) as '平均CPU时间ms',
sum(reads) as '总读次数',
avg(reads) as '平均读次数',
avg(writes) as '平均写次数'
from TabSQL
group by replace(replace(replace( substring(Textdata,1,6600) ,char(10),' '),char(13),' ') ,char(9),' ') ,LoginName
order by sum(reads) desc
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最耗CPU的SQL
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SELECT TOP 100 replace(replace(replace( substring(Textdata,1,6600) ,char(10),' '),char(13),' ') ,char(9),' ') as '名称',LoginName,
count(*) as '数量',
sum(duration/1000) as '总执行时间ms',
avg(duration/1000) as '平均执行时间ms',
sum(cpu) as '总CPU时间',
avg(cpu) as '平均CPU时间',
avg(reads) as '平均读次数',
avg(writes) as '平均写次数'
from TabSQL
group by replace(replace(replace( substring(Textdata,1,6600) ,char(10),' '),char(13),' ') ,char(9),' ') ,LoginName
order by avg(cpu) desc
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