SQLSERVER排查CPU占用高的情况

时间:2024-01-14 18:21:08

SQLSERVER排查CPU占用高的情况

今天中午,有朋友叫我帮他看一下数据库,操作系统是Windows2008R2 ,数据库是SQL2008R2 64位

64G内存,16核CPU

硬件配置还是比较高的,他说服务器运行的是金蝶K3软件,数据库实例里有多个数据库

他说是这几天才出现的,而且在每天的某一个时间段才会出现CPU占用高的情况

内存占用也很高,占用了30个G

SQLSERVER排查CPU占用高的情况

SQLSERVER排查CPU占用高的情况

-----------------------------------------------华丽的分割线-------------------------------------------------------

一般排查都是用下面的脚本,一般会用到三个视图sys.sysprocesses ,dm_exec_sessions ,dm_exec_requests

 USE master
GO
--如果要指定数据库就把注释去掉
SELECT * FROM sys.[sysprocesses] WHERE [spid]>50 --AND DB_NAME([dbid])='gposdb'
SELECT COUNT(*) FROM [sys].[dm_exec_sessions] WHERE [session_id]>50

看一下当前的数据库用户连接有多少

然后使用下面语句看一下各项指标是否正常,是否有阻塞,这个语句选取了前10个最耗CPU时间的会话

SQLSERVER排查CPU占用高的情况
 SELECT TOP 10
[session_id],
[request_id],
[start_time] AS '开始时间',
[status] AS '状态',
[command] AS '命令',
dest.[text] AS 'sql语句',
DB_NAME([database_id]) AS '数据库名',
[blocking_session_id] AS '正在阻塞其他会话的会话ID',
[wait_type] AS '等待资源类型',
[wait_time] AS '等待时间',
[wait_resource] AS '等待的资源',
[reads] AS '物理读次数',
[writes] AS '写次数',
[logical_reads] AS '逻辑读次数',
[row_count] AS '返回结果行数'
FROM sys.[dm_exec_requests] AS der
CROSS APPLY
sys.[dm_exec_sql_text](der.[sql_handle]) AS dest
WHERE [session_id]>50 AND DB_NAME(der.[database_id])='gposdb'
ORDER BY [cpu_time] DESC
SQLSERVER排查CPU占用高的情况

如果想看具体的SQL语句可以执行下面的SQL语句,记得在SSMS里选择以文本格式显示结果

SQLSERVER排查CPU占用高的情况
 --在SSMS里选择以文本格式显示结果
SELECT TOP 10
dest.[text] AS 'sql语句'
FROM sys.[dm_exec_requests] AS der
CROSS APPLY
sys.[dm_exec_sql_text](der.[sql_handle]) AS dest
WHERE [session_id]>50
ORDER BY [cpu_time] DESC
SQLSERVER排查CPU占用高的情况

SQLSERVER排查CPU占用高的情况

模拟了一些耗CPU时间的动作

SQLSERVER排查CPU占用高的情况

SQLSERVER排查CPU占用高的情况

SQLSERVER排查CPU占用高的情况

-----------------------------------------华丽的分割线-----------------------------------------------------------

还有查看CPU数和user scheduler数和最大工作线程数,检查worker是否用完也可以排查CPU占用情况

 --查看CPU数和user scheduler数目
SELECT cpu_count,scheduler_count FROM sys.dm_os_sys_info
--查看最大工作线程数
SELECT max_workers_count FROM sys.dm_os_sys_info

查看机器上的所有schedulers包括user 和system
通过下面语句可以看到worker是否用完,当达到最大线程数的时候就要检查blocking了

对照下面这个表
各种CPU和SQLSERVER版本组合自动配置的最大工作线程数
CPU数                 32位计算机                        64位计算机
<=4                     256                                   512
  8                        288                                   576
 16                       352                                   704
 32                       480                                   960

SQLSERVER排查CPU占用高的情况
 SELECT
scheduler_address,
scheduler_id,
cpu_id,
status,
current_tasks_count,
current_workers_count,active_workers_count
FROM sys.dm_os_schedulers
SQLSERVER排查CPU占用高的情况

如果大家有什么需要补充的,或者文章有不正确的,欢迎大家拍砖!!

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2013-6-15 做了一下补充,如果SQLSERVER存在要等待的资源,那么执行下面语句就会显示出会话中有多少个worker在等待

结合[sys].[dm_os_wait_stats]视图,如果当前SQLSERVER里面没有任何等待资源,那么下面的SQL语句不会显示任何结果

SQLSERVER排查CPU占用高的情况
 SELECT TOP 10
[session_id],
[request_id],
[start_time] AS '开始时间',
[status] AS '状态',
[command] AS '命令',
dest.[text] AS 'sql语句',
DB_NAME([database_id]) AS '数据库名',
[blocking_session_id] AS '正在阻塞其他会话的会话ID',
der.[wait_type] AS '等待资源类型',
[wait_time] AS '等待时间',
[wait_resource] AS '等待的资源',
[dows].[waiting_tasks_count] AS '当前正在进行等待的任务数',
[reads] AS '物理读次数',
[writes] AS '写次数',
[logical_reads] AS '逻辑读次数',
[row_count] AS '返回结果行数'
FROM sys.[dm_exec_requests] AS der
INNER JOIN [sys].[dm_os_wait_stats] AS dows
ON der.[wait_type]=[dows].[wait_type]
CROSS APPLY
sys.[dm_exec_sql_text](der.[sql_handle]) AS dest
WHERE [session_id]>50
ORDER BY [cpu_time] DESC
SQLSERVER排查CPU占用高的情况

比如我当前执行了查询SalesOrderDetail_test表100次,由于表数据非常多,所以SSMS需要把SQLSERVER执行的结果慢慢的取走,

造成了ASYNC_NETWORK_IO等待

 USE [AdventureWorks]
GO
SELECT * FROM dbo.[SalesOrderDetail_test]
GO 100

SQLSERVER排查CPU占用高的情况

------------------------------------------------------------------------------------------------

经过排查和这几天的观察情况,确定是某些表缺失索引导致,现在在这些表上增加了索引,问题解决了

SQLSERVER排查CPU占用高的情况
 select * from t_AccessControl        --权限控制表权限控制
select * from t_GroupAccess --用户组权限表用户组权限
select * from t_GroupAccessType --用户组权限类表用户组权限类
select * from t_ObjectAccess --对象权限表对象权限
select * from t_ObjectAccessType --对象权限类型表对象权限类型
select * from t_ObjectType --对象类型表对象类型
SQLSERVER排查CPU占用高的情况

查询CPU占用高的语句

SQLSERVER排查CPU占用高的情况
 SELECT TOP 10
total_worker_time/execution_count AS avg_cpu_cost, plan_handle,
execution_count,
(SELECT SUBSTRING(text, statement_start_offset/2 + 1,
(CASE WHEN statement_end_offset = -1
THEN LEN(CONVERT(nvarchar(max), text)) * 2
ELSE statement_end_offset
END - statement_start_offset)/2)
FROM sys.dm_exec_sql_text(sql_handle)) AS query_text
FROM sys.dm_exec_query_stats
ORDER BY [avg_cpu_cost] DESC
SQLSERVER排查CPU占用高的情况

SQLSERVER排查CPU占用高的情况

查询缺失索引

SQLSERVER排查CPU占用高的情况
 SELECT
DatabaseName = DB_NAME(database_id)
,[Number Indexes Missing] = count(*)
FROM sys.dm_db_missing_index_details
GROUP BY DB_NAME(database_id)
ORDER BY 2 DESC;
SQLSERVER排查CPU占用高的情况
SQLSERVER排查CPU占用高的情况
 SELECT  TOP 10
[Total Cost] = ROUND(avg_total_user_cost * avg_user_impact * (user_seeks + user_scans),0)
, avg_user_impact
, TableName = statement
, [EqualityUsage] = equality_columns
, [InequalityUsage] = inequality_columns
, [Include Cloumns] = included_columns
FROM sys.dm_db_missing_index_groups g
INNER JOIN sys.dm_db_missing_index_group_stats s
ON s.group_handle = g.index_group_handle
INNER JOIN sys.dm_db_missing_index_details d
ON d.index_handle = g.index_handle
ORDER BY [Total Cost] DESC;
SQLSERVER排查CPU占用高的情况

SQLSERVER排查CPU占用高的情况

SQLSERVER排查CPU占用高的情况

定位问题后,新建非聚集索引

SQLSERVER排查CPU占用高的情况
 CREATE NONCLUSTERED INDEX IX_t_AccessControl_F4 ON dbo.t_AccessControl
(
FObjectType
)include([FUserID], [FAccessType], [FAccessMask]) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO drop index IX_t_AccessControl_F4 on t_AccessControl
SQLSERVER排查CPU占用高的情况

CPU占用恢复正常

SQLSERVER排查CPU占用高的情况

跟踪模板和跟踪文件下载,请使用SQL2008R2 版本:files.cnblogs.com/lyhabc/跟踪模板和trace.rar