在Microsoft SQL Server如何获得查询/存储过程的查询执行计划?
当前回答
在SQL Server Management Studio:
“Ctrl + M”将生成实际执行计划
“Ctrl + L”将生成估计执行计划
“Shift + Alt + S”为客户端统计
“Ctrl + Alt + P”用于SQL Server Profiler中的跟踪查询。
其他回答
从SQL Server 2016+开始,引入了查询存储功能来监控性能。它提供了对查询计划选择和性能的洞察。 它并不是跟踪或扩展事件的完全替代,但随着它从一个版本到另一个版本的发展,我们可能会在SQL Server的未来版本中得到一个功能齐全的查询存储。 查询存储的主要流程
SQL Server existing components interact with query store by utilising Query Store Manager. Query Store Manager determines which Store should be used and then passes execution to that store (Plan or Runtime Stats or Query Wait Stats) Plan Store - Persisting the execution plan information Runtime Stats Store - Persisting the execution statistics information Query Wait Stats Store - Persisting wait statistics information. Plan, Runtime Stats and Wait store uses Query Store as an extension to SQL Server.
Enabling the Query Store: Query Store works at the database level on the server. Query Store is not active for new databases by default. You cannot enable the query store for the master or tempdb database. Available DMV sys.database_query_store_options (Transact-SQL) Collect Information in the Query Store: We collect all the available information from the three stores using Query Store DMV (Data Management Views). Query Plan Store: Persisting the execution plan information and it is accountable for capturing all information that is related to query compilation. sys.query_store_query (Transact-SQL) sys.query_store_plan (Transact-SQL) sys.query_store_query_text (Transact-SQL) Runtime Stats Store: Persisting the execution statistics information and it is probably the most frequently updated store. These statistics represent query execution data. sys.query_store_runtime_stats (Transact-SQL) Query Wait Stats Store: Persisting and capturing wait statistics information. sys.query_store_wait_stats (Transact-SQL)
注意:查询等待统计数据存储仅在SQL Server 2017+中可用
我最喜欢的获取和深入分析查询执行计划的工具是SQL Sentry Plan Explorer。它在执行计划的细节分析和可视化方面比SSMS更加人性化、方便和全面。
下面是一个示例屏幕截图,让你了解这个工具提供了什么功能:
它只是工具中可用的视图之一。注意应用程序窗口底部的一组选项卡,它可以让你获得不同类型的执行计划表示以及有用的附加信息。
此外,我还没有发现它的免费版有任何限制,会阻止你每天使用它,或者迫使你最终购买专业版。所以,如果你更喜欢使用免费版,没有什么能阻止你这么做。
预估执行计划
估计的执行计划是由Optimizer在不运行SQL查询的情况下生成的。
为了获得估计的执行计划,您需要在执行查询之前启用SHOWPLAN_ALL设置。
SET SHOWPLAN_ALL ON
现在,当执行以下SQL查询时:
SELECT p.id
FROM post p
WHERE EXISTS (
SELECT 1
FROM post_comment pc
WHERE
pc.post_id = p.id AND
pc.review = 'Bingo'
)
ORDER BY p.title
OFFSET 20 ROWS
FETCH NEXT 10 ROWS ONLY
SQL Server将生成以下估计的执行计划:
| NodeId | Parent | LogicalOp | EstimateRows | EstimateIO | EstimateCPU | AvgRowSize | TotalSubtreeCost | EstimateExecutions |
|--------|--------|----------------------|--------------|-------------|-------------|------------|------------------|--------------------|
| 1 | 0 | NULL | 10 | NULL | NULL | NULL | 0.03374284 | NULL |
| 2 | 1 | Top | 10 | 0 | 3.00E-06 | 15 | 0.03374284 | 1 |
| 4 | 2 | Distinct Sort | 30 | 0.01126126 | 0.000504114 | 146 | 0.03373984 | 1 |
| 5 | 4 | Inner Join | 46.698 | 0 | 0.00017974 | 146 | 0.02197446 | 1 |
| 6 | 5 | Clustered Index Scan | 43 | 0.004606482 | 0.0007543 | 31 | 0.005360782 | 1 |
| 7 | 5 | Clustered Index Seek | 1 | 0.003125 | 0.0001581 | 146 | 0.0161733 | 43 |
在运行我们想要获得估计执行计划的查询之后,您需要禁用SHOWPLAN_ALL,否则,当前数据库会话将只生成估计的执行计划,而不是执行提供的SQL查询。
SET SHOWPLAN_ALL OFF
SQL Server Management Studio估计计划
在SQL Server Management Studio应用程序中,您可以通过按CTRL+L快捷键轻松获得任何SQL查询的估计执行计划。
实际执行计划
实际的SQL执行计划由Optimizer在运行SQL查询时生成。如果数据库表统计信息是准确的,那么实际计划应该与估计的计划没有太大差异。
要获得SQL Server上的实际执行计划,需要启用STATISTICS IO, TIME, PROFILE设置,如下SQL命令所示:
SET STATISTICS IO, TIME, PROFILE ON
现在,当运行前面的查询时,SQL Server将生成以下执行计划:
| Rows | Executes | NodeId | Parent | LogicalOp | EstimateRows | EstimateIO | EstimateCPU | AvgRowSize | TotalSubtreeCost |
|------|----------|--------|--------|----------------------|--------------|-------------|-------------|------------|------------------|
| 10 | 1 | 1 | 0 | NULL | 10 | NULL | NULL | NULL | 0.03338978 |
| 10 | 1 | 2 | 1 | Top | 1.00E+01 | 0 | 3.00E-06 | 15 | 0.03338978 |
| 30 | 1 | 4 | 2 | Distinct Sort | 30 | 0.01126126 | 0.000478783 | 146 | 0.03338679 |
| 41 | 1 | 5 | 4 | Inner Join | 44.362 | 0 | 0.00017138 | 146 | 0.02164674 |
| 41 | 1 | 6 | 5 | Clustered Index Scan | 41 | 0.004606482 | 0.0007521 | 31 | 0.005358581 |
| 41 | 41 | 7 | 5 | Clustered Index Seek | 1 | 0.003125 | 0.0001581 | 146 | 0.0158571 |
SQL Server parse and compile time:
CPU time = 8 ms, elapsed time = 8 ms.
(10 row(s) affected)
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'post'. Scan count 0, logical reads 116, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'post_comment'. Scan count 1, logical reads 5, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
(6 row(s) affected)
SQL Server Execution Times:
CPU time = 0 ms, elapsed time = 1 ms.
运行查询后,我们感兴趣的是获得实际的执行计划,你需要禁用STATISTICS IO, TIME, PROFILE ON设置,如下所示:
SET STATISTICS IO, TIME, PROFILE OFF
SQL Server Management Studio实际计划
在SQL Server Management Studio应用程序中,您可以通过按CTRL+M快捷键轻松获得任何SQL查询的估计执行计划。
除了已经发布的综合答案之外,有时能够以编程方式访问执行计划以提取信息也是有用的。下面是示例代码。
DECLARE @TraceID INT
EXEC StartCapture @@SPID, @TraceID OUTPUT
EXEC sp_help 'sys.objects' /*<-- Call your stored proc of interest here.*/
EXEC StopCapture @TraceID
StartCapture定义
CREATE PROCEDURE StartCapture
@Spid INT,
@TraceID INT OUTPUT
AS
DECLARE @maxfilesize BIGINT = 5
DECLARE @filepath NVARCHAR(200) = N'C:\trace_' + LEFT(NEWID(),36)
EXEC sp_trace_create @TraceID OUTPUT, 0, @filepath, @maxfilesize, NULL
exec sp_trace_setevent @TraceID, 122, 1, 1
exec sp_trace_setevent @TraceID, 122, 22, 1
exec sp_trace_setevent @TraceID, 122, 34, 1
exec sp_trace_setevent @TraceID, 122, 51, 1
exec sp_trace_setevent @TraceID, 122, 12, 1
-- filter for spid
EXEC sp_trace_setfilter @TraceID, 12, 0, 0, @Spid
-- start the trace
EXEC sp_trace_setstatus @TraceID, 1
停止捕获定义
CREATE PROCEDURE StopCapture
@TraceID INT
AS
WITH XMLNAMESPACES ('http://schemas.microsoft.com/sqlserver/2004/07/showplan' as sql),
CTE
as (SELECT CAST(TextData AS VARCHAR(MAX)) AS TextData,
ObjectID,
ObjectName,
EventSequence,
/*costs accumulate up the tree so the MAX should be the root*/
MAX(EstimatedTotalSubtreeCost) AS EstimatedTotalSubtreeCost
FROM fn_trace_getinfo(@TraceID) fn
CROSS APPLY fn_trace_gettable(CAST(value AS NVARCHAR(200)), 1)
CROSS APPLY (SELECT CAST(TextData AS XML) AS xPlan) x
CROSS APPLY (SELECT T.relop.value('@EstimatedTotalSubtreeCost',
'float') AS EstimatedTotalSubtreeCost
FROM xPlan.nodes('//sql:RelOp') T(relop)) ca
WHERE property = 2
AND TextData IS NOT NULL
AND ObjectName not in ( 'StopCapture', 'fn_trace_getinfo' )
GROUP BY CAST(TextData AS VARCHAR(MAX)),
ObjectID,
ObjectName,
EventSequence)
SELECT ObjectName,
SUM(EstimatedTotalSubtreeCost) AS EstimatedTotalSubtreeCost
FROM CTE
GROUP BY ObjectID,
ObjectName
-- Stop the trace
EXEC sp_trace_setstatus @TraceID, 0
-- Close and delete the trace
EXEC sp_trace_setstatus @TraceID, 2
GO
假设您正在使用Microsoft SQL Server Management Studio
对于估计的查询计划,可以按Ctrl + L或以下按钮。
对于“实际查询计划”,可以按“Ctrl +” M或以下按钮,然后执行查询。
对于实时查询计划,(仅在SSMS 2016中)在执行查询之前使用以下按钮。
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