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
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
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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
1 USE master 2 GO 3 -- 如果要指定数据库就把注释去掉 4 SELECT * FROM sys. [ sysprocesses ] WHERE [ spid ] > 50 -- AND DB_NAME([dbid])='gposdb' 5 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
1 SELECT TOP 10 2 [ session_id ] , 3 [ request_id ] , 4 [ start_time ] AS ' 开始时间 ' , 5 [ status ] AS ' 状态 ' , 6 [ command ] AS ' 命令 ' , 7 dest. [ text ] AS ' sql语句 ' , 8 DB_NAME( [ database_id ]) AS ' 数据库名 ' , 9 [ blocking_session_id ] AS ' 正在阻塞其他会话的会话ID ' , 10 [ wait_type ] AS ' 等待资源类型 ' , 11 [ wait_time ] AS ' 等待时间 ' , 12 [ wait_resource ] AS ' 等待的资源 ' , 13 [ reads ] AS ' 物理读次数 ' , 14 [ writes ] AS ' 写次数 ' , 15 [ logical_reads ] AS ' 逻辑读次数 ' , 16 [ row_count ] AS ' 返回结果行数 ' 17 FROM sys. [ dm_exec_requests ] AS der 18 CROSS APPLY 19 sys. [ dm_exec_sql_text ](der. [ sql_handle ]) AS dest 20 WHERE [ session_id ] > 50 AND DB_NAME(der. [ database_id ]) = ' gposdb ' 21 ORDER BY [ cpu_time ] DESC
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
1 -- 在SSMS里选择以文本格式显示结果 2 SELECT TOP 10 3 dest. [ text ] AS ' sql语句 ' 4 FROM sys. [ dm_exec_requests ] AS der 5 CROSS APPLY 6 sys. [ dm_exec_sql_text ](der. [ sql_handle ]) AS dest 7 WHERE [ session_id ] > 50 8 ORDER BY [ cpu_time ] DESC
模拟了一些耗CPU时间的动作
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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
1 -- 查看CPU数和user scheduler数目 2 SELECT cpu_count,scheduler_count FROM sys.dm_os_sys_info 3 -- 查看最大工作线程数 4 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
1 SELECT 2 scheduler_address, 3 scheduler_id, 4 cpu_id, 5 status, 6 current_tasks_count, 7 current_workers_count,active_workers_count 8 FROM sys.dm_os_schedulers
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
1 SELECT TOP 10 2 [ session_id ] , 3 [ request_id ] , 4 [ start_time ] AS ' 开始时间 ' , 5 [ status ] AS ' 状态 ' , 6 [ command ] AS ' 命令 ' , 7 dest. [ text ] AS ' sql语句 ' , 8 DB_NAME( [ database_id ]) AS ' 数据库名 ' , 9 [ blocking_session_id ] AS ' 正在阻塞其他会话的会话ID ' , 10 der. [ wait_type ] AS ' 等待资源类型 ' , 11 [ wait_time ] AS ' 等待时间 ' , 12 [ wait_resource ] AS ' 等待的资源 ' , 13 [ dows ]. [ waiting_tasks_count ] AS ' 当前正在进行等待的任务数 ' , 14 [ reads ] AS ' 物理读次数 ' , 15 [ writes ] AS ' 写次数 ' , 16 [ logical_reads ] AS ' 逻辑读次数 ' , 17 [ row_count ] AS ' 返回结果行数 ' 18 FROM sys. [ dm_exec_requests ] AS der 19 INNER JOIN [ sys ]. [ dm_os_wait_stats ] AS dows 20 ON der. [ wait_type ] = [ dows ]. [ wait_type ] 21 CROSS APPLY 22 sys. [ dm_exec_sql_text ](der. [ sql_handle ]) AS dest 23 WHERE [ session_id ] > 50 24 ORDER BY [ cpu_time ] DESC
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
1 USE [ AdventureWorks ] 2 GO 3 SELECT * FROM dbo. [ SalesOrderDetail_test ] 4 GO 100
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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
1 select * from t_AccessControl -- 权限控制表权限控制 2 select * from t_GroupAccess -- 用户组权限表用户组权限 3 select * from t_GroupAccessType -- 用户组权限类表用户组权限类 4 select * from t_ObjectAccess -- 对象权限表对象权限 5 select * from t_ObjectAccessType -- 对象权限类型表对象权限类型 6 select * from t_ObjectType -- 对象类型表对象类型
查询CPU占用高的语句
1 SELECT TOP 10 2 total_worker_time /execution_count AS avg_cpu_cost, plan_handle, 3 execution_count, 4 ( SELECT SUBSTRING( text, statement_start_offset / 2 + 1 , 5 ( CASE WHEN statement_end_offset = - 1 6 THEN LEN( CONVERT( nvarchar( max), text)) * 2 7 ELSE statement_end_offset 8 END - statement_start_offset) / 2 ) 9 FROM sys.dm_exec_sql_text(sql_handle)) AS query_text 10 FROM sys.dm_exec_query_stats 11 ORDER BY [ avg_cpu_cost ] DESC
查询缺失索引
1 SELECT 2 DatabaseName = DB_NAME (database_id) 3 , [ Number Indexes Missing ] = count( * ) 4 FROM sys.dm_db_missing_index_details 5 GROUP BY DB_NAME (database_id) 6 ORDER BY 2 DESC;
1 SELECT TOP 10 2 [ Total Cost ] = ROUND(avg_total_user_cost * avg_user_impact * (user_seeks + user_scans), 0 ) 3 , avg_user_impact 4 , TableName = statement 5 , [ EqualityUsage ] = equality_columns 6 , [ InequalityUsage ] = inequality_columns 7 , [ Include Cloumns ] = included_columns 8 FROM sys.dm_db_missing_index_groups g 9 INNER JOIN sys.dm_db_missing_index_group_stats s 10 ON s.group_handle = g.index_group_handle 11 INNER JOIN sys.dm_db_missing_index_details d 12 ON d.index_handle = g.index_handle 13 ORDER BY [ Total Cost ] DESC;
定位问题后，新建非聚集索引
1 CREATE NONCLUSTERED INDEX IX_t_AccessControl_F4 ON dbo.t_AccessControl 2 ( 3 FObjectType 4 )include( [ FUserID ], [ FAccessType ], [ FAccessMask ]) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [ PRIMARY ] 5 GO 6 7 drop index IX_t_AccessControl_F4 on t_AccessControl
CPU占用恢复正常
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