除了前面所说的，还有一件重要的事情需要知道。

Query plans are often too complex to be represented by the built-in XML column type which has a limitation of 127 levels of nested elements. That is one of the reasons why sys.dm_exec_query_plan may return NULL or even throw an error in earlier MS SQL versions, so generally it's safer to use sys.dm_exec_text_query_plan instead. The latter also has a useful bonus feature of selecting a plan for a particular statement rather than the whole batch. Here's how you use it to view plans for currently running statements:

SELECT p.query_plan
FROM sys.dm_exec_requests AS r
OUTER APPLY sys.dm_exec_text_query_plan(
                r.plan_handle,
                r.statement_start_offset,
                r.statement_end_offset) AS p

然而，与XML列相比，结果表中的文本列不是很方便。为了能够单击要在单独的选项卡中作为图表打开的结果，而不必将其内容保存到文件中，您可以使用一个小技巧(记住您不能只使用CAST(…AS XML))，尽管这将只适用于单行:

SELECT Tag = 1, Parent = NULL, [ShowPlanXML!1!!XMLTEXT] = query_plan
FROM sys.dm_exec_text_query_plan(
                -- set these variables or copy values
                -- from the results of the above query
                @plan_handle,
                @statement_start_offset,
                @statement_end_offset)
FOR XML EXPLICIT

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

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

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。

您也可以通过powershell使用SET STATISTICS XML ON来获得实际的计划。我写它是为了将多语句计划合并为一个计划;

    ########## BEGIN : SCRIPT VARIABLES #####################
    [string]$server = '.\MySQLServer'
    [string]$database = 'MyDatabase'
    [string]$sqlCommand = 'EXEC sp_ExampleSproc'
    [string]$XMLOutputFileName = 'sp_ExampleSproc'
    [string]$XMLOutputPath = 'C:\SQLDumps\ActualPlans\'
    ########## END   : SCRIPT VARIABLES #####################

    #Set up connection
    $connectionString = "Persist Security Info=False;Integrated Security=true;Connection Timeout=0;Initial Catalog=$database;Server=$server"
    $connection = new-object system.data.SqlClient.SQLConnection($connectionString)

    #Set up commands
    $command = new-object system.data.sqlclient.sqlcommand($sqlCommand,$connection)
    $command.CommandTimeout = 0
    $commandXMLActPlanOn = new-object system.data.sqlclient.sqlcommand("SET STATISTICS XML ON",$connection)
    $commandXMLActPlanOff = new-object system.data.sqlclient.sqlcommand("SET STATISTICS XML OFF",$connection)

    $connection.Open()

    #Enable session XML plan
    $result = $commandXMLActPlanOn.ExecuteNonQuery()

    #Execute SP and return resultsets into a dataset
    $adapter = New-Object System.Data.sqlclient.sqlDataAdapter $command
    $dataset = New-Object System.Data.DataSet
    $adapter.Fill($dataSet) | Out-Null

    #Set up output file name and path
    [string]$fileNameDateStamp = get-date -f yyyyMMdd_HHmmss
    [string]$XMLOutputFilePath = "$XMLOutputPath$XMLOutputFileName`_$fileNameDateStamp.sqlplan"

    #Pull XML plans out of dataset and merge into one multi-statement plan
    [int]$cntr = 1
    ForEach($table in $dataset.Tables)
    {
            if($table.Columns[0].ColumnName -eq "Microsoft SQL Server 2005 XML Showplan")
            {

                [string]$fullXMLPlan = $Table.rows[0]."Microsoft SQL Server 2005 XML Showplan"

                if($cntr -eq 1)
                    {

                    [regex]$rx = "\<ShowPlanXML xmlns\=.{1,}\<Statements\>"
                    [string]$startXMLPlan = $rx.Match($fullXMLPlan).Value
                    [regex]$rx = "\<\/Statements\>.{1,}\<\/ShowPlanXML\>"
                    [string]$endXMLPlan = $rx.Match($fullXMLPlan).Value

                    $startXMLPlan | out-file -Append -FilePath $XMLOutputFilePath

                    }

                [regex]$rx = "\<StmtSimple.{1,}\<\/StmtSimple\>"
                [string]$bodyXMLPlan = $rx.Match($fullXMLPlan).Value

                $bodyXMLPlan | out-file -Append -FilePath $XMLOutputFilePath

                $cntr += 1
            } 
    }

    $endXMLPlan | out-file -Append -FilePath $XMLOutputFilePath

    #Disable session XML plan
    $result = $commandXMLActPlanOff.ExecuteNonQuery()

    $connection.Close()

除了前面所说的，还有一件重要的事情需要知道。

Query plans are often too complex to be represented by the built-in XML column type which has a limitation of 127 levels of nested elements. That is one of the reasons why sys.dm_exec_query_plan may return NULL or even throw an error in earlier MS SQL versions, so generally it's safer to use sys.dm_exec_text_query_plan instead. The latter also has a useful bonus feature of selecting a plan for a particular statement rather than the whole batch. Here's how you use it to view plans for currently running statements:

SELECT p.query_plan
FROM sys.dm_exec_requests AS r
OUTER APPLY sys.dm_exec_text_query_plan(
                r.plan_handle,
                r.statement_start_offset,
                r.statement_end_offset) AS p

然而，与XML列相比，结果表中的文本列不是很方便。为了能够单击要在单独的选项卡中作为图表打开的结果，而不必将其内容保存到文件中，您可以使用一个小技巧(记住您不能只使用CAST(…AS XML))，尽管这将只适用于单行:

SELECT Tag = 1, Parent = NULL, [ShowPlanXML!1!!XMLTEXT] = query_plan
FROM sys.dm_exec_text_query_plan(
                -- set these variables or copy values
                -- from the results of the above query
                @plan_handle,
                @statement_start_offset,
                @statement_end_offset)
FOR XML EXPLICIT