操作系统是Windows2008R2 ,数据库是SQL2014 64位。

　　近阶段服务器出现过几次死机，管理员反馈机器内存使用率100%导致机器卡死。于是做了个监测服务器的软件实时记录CPU数据，几日观察得出数据如下：

　　SQL优化方法：

　　1、查看连接对象

1 USE master2 GO3 --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'

　　

　　当前连接对象有67个其中‘WINAME’的主机名，‘jTDS’的进程名不属于已知常用软件，找到这台主机并解决连接问题。在360流量防火墙中查看有哪个软件连接了服务器IP，除之。

2、然后使用下面语句看一下各项指标是否正常，是否有阻塞，正常情况下搜索结果应该为空。

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

查看是哪些SQL语句占用较大可以使用下面代码

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

3、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

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

4、查询CPU占用最高的SQL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_text10 FROM sys.dm_exec_query_stats11 ORDER BY [avg_cpu_cost] DESC

5、索引缺失查询

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; 7 SELECT  TOP 10  8         [Total Cost]  = ROUND(avg_total_user_cost * avg_user_impact * (user_seeks + user_scans),0)  9         , avg_user_impact10         , TableName = statement11         , [EqualityUsage] = equality_columns 12         , [InequalityUsage] = inequality_columns13         , [Include Cloumns] = included_columns14 FROM        sys.dm_db_missing_index_groups g 15 INNER JOIN    sys.dm_db_missing_index_group_stats s 16        ON s.group_handle = g.index_group_handle 17 INNER JOIN    sys.dm_db_missing_index_details d 18        ON d.index_handle = g.index_handle19 ORDER BY [Total Cost] DESC;

　　找到索引缺失的表，根据查询结果中的关键次逐一建立索引。

　　做完这些测试，基本能找到问题。