【轉載】SQL Server中查詢CPU佔用高的SQL語句

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本文導讀：觸發器造成死結、作業多且頻繁、中間表的大量使用、遊標的大量使用、索引的設計不合理、事務操作頻繁、SQL語句設計不合理，都會造成查詢效率低下、影響伺服器效能的發揮。我們可以使用sql server內建的效能分析追蹤工具sql profiler分析資料庫設計所產生問題的來源，進行有針對性的處理；下面介紹SQL Server中如何查詢CPU佔用高的SQL語句

SQL Server中查詢CPU佔用高的情況，會用到sys.sysprocesses ,dm_exec_sessions ,dm_exec_requests

 

一、查看當前的資料庫使用者串連有多少

 

USE master

GO

SELECT * FROM sys.[sysprocesses] WHERE [spid]>50 --AND DB_NAME([dbid])=‘gposdb‘

SELECT COUNT(*) FROM [sys].[dm_exec_sessions] WHERE [session_id]>50

 

二、選取前10個最耗CPU時間的會話

 

 SQL 代碼   複製

SELECT TOP 10 

[session_id], 

[request_id], 

[start_time] AS ‘開始時間‘, 

[status] AS ‘狀態‘, 

[command] AS ‘命令‘, 

dest.[text] AS ‘sql語句‘, 

DB_NAME([database_id]) AS ‘資料庫名‘, 

[blocking_session_id] AS ‘正在阻塞其他會話的會話ID‘, 

[wait_type] AS ‘等待資源類型‘, 

[wait_time] AS ‘等待時間‘, 

[wait_resource] AS ‘等待的資源‘, 

[reads] AS ‘物理讀次數‘, 

[writes] AS ‘寫次數‘, 

[logical_reads] AS ‘邏輯讀次數‘, 

[row_count] AS ‘返回結果行數‘ 

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 

 

三、查詢前10個最耗CPU時間的SQL語句

 

 SQL 代碼   複製

--在SSMS裡選擇以文字格式設定顯示結果 

SELECT TOP 10 

dest.[text] AS ‘sql語句‘ 

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 

 

四、查詢會話中有多少個worker在等待 

 

 SQL 代碼   複製

SELECT TOP 10 

 [session_id], 

 [request_id], 

 [start_time] AS ‘開始時間‘, 

 [status] AS ‘狀態‘, 

 [command] AS ‘命令‘, 

 dest.[text] AS ‘sql語句‘, 

 DB_NAME([database_id]) AS ‘資料庫名‘, 

 [blocking_session_id] AS ‘正在阻塞其他會話的會話ID‘, 

 der.[wait_type] AS ‘等待資源類型‘, 

 [wait_time] AS ‘等待時間‘, 

 [wait_resource] AS ‘等待的資源‘, 

 [dows].[waiting_tasks_count] AS ‘當前進行中等待的任務數‘, 

 [reads] AS ‘物理讀次數‘, 

 [writes] AS ‘寫次數‘, 

 [logical_reads] AS ‘邏輯讀次數‘, 

 [row_count] AS ‘返回結果行數‘ 

 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 

 

五、查詢CPU佔用高的語句

 

 SQL 代碼   複製

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 

【轉載】SQL Server中查詢CPU佔用高的SQL語句