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2024-03-15 07:00:00

SQL Server:查询速度快，但过程慢

查询运行得很快:

DECLARE @SessionGUID uniqueidentifier
SET @SessionGUID = 'BCBA333C-B6A1-4155-9833-C495F22EA908'

SELECT *
FROM Report_Opener
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank

子树成本:0.502

但是将相同的SQL放在存储过程中运行缓慢，并且执行计划完全不同

CREATE PROCEDURE dbo.ViewOpener @SessionGUID uniqueidentifier AS
SELECT *
FROM Report_Opener
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank

EXECUTE ViewOpener @SessionGUID

子树代价:19.2

我已经运行

sp_recompile ViewOpener

它仍然运行相同(糟糕)，我也改变了存储 过程

CREATE PROCEDURE dbo.ViewOpener @SessionGUID uniqueidentifier AS
SELECT *, 'recompile please'
FROM Report_Opener
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank

然后再回来，试图欺骗它重新编译。

我已经删除并重新创建了存储过程，以便让它生成一个新的计划。

我尝试过强制重新编译，并通过使用诱饵变量防止参数嗅探:

CREATE PROCEDURE dbo.ViewOpener @SessionGUID uniqueidentifier AS

DECLARE @SessionGUIDbitch uniqueidentifier
SET @SessionGUIDbitch = @SessionGUID

SELECT *
FROM Report_Opener
WHERE SessionGUID = @SessionGUIDbitch
ORDER BY CurrencyTypeOrder, Rank

我还尝试过用RECOMPILE定义存储过程:

CREATE PROCEDURE dbo.ViewOpener @SessionGUID uniqueidentifier 
WITH RECOMPILE
AS
SELECT *
FROM Report_Opener
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank

所以它的计划永远不会被缓存，我已经尝试在执行时强制重新编译:

EXECUTE ViewOpener @SessionGUID WITH RECOMPILE

这并没有帮助。

我已经尝试将过程转换为动态SQL:

CREATE PROCEDURE dbo.ViewOpener @SessionGUID uniqueidentifier 
WITH RECOMPILE AS
DECLARE @SQLString NVARCHAR(500)

SET @SQLString = N'SELECT *
   FROM Report_OpenerTest
   WHERE SessionGUID = @SessionGUID
   ORDER BY CurrencyTypeOrder, Rank'

EXECUTE sp_executesql @SQLString,
N'@SessionGUID uniqueidentifier',
@SessionGUID

这并没有帮助。

实体“Report_Opener”是一个没有索引的视图。视图只引用底层表。没有表包含计算列、索引列或其他列。

为了它的地狱，我尝试创建视图

SET ANSI_NULLS ON
SET QUOTED_IDENTIFER ON

这并没有解决问题。

这是怎么回事

查询速度很快 将查询移动到视图，并从视图中进行选择非常快 从存储过程的视图中进行选择是否慢了40倍?

我尝试将视图的定义直接移动到存储过程中(违反了3条业务规则，并破坏了一个重要的封装)，这使得它只慢了大约6倍。

为什么存储过程版本这么慢?为什么SQL Server运行ad-hoc SQL比另一种ad-hoc SQL快呢?

我真的不愿意

在代码中嵌入SQL 完全更改代码 Microsoft SQL Server 2000 - 8.00.2050 (Intel X86) 2008年3月7日21:29:56 版权所有(c) 1988-2003微软公司 Windows NT 5.2标准版(Build 3790: Service Pack 2)

但是，如果没有参数嗅探，SQL Server不能像SQL Server运行查询一样快，这是什么原因呢?

我的下一个尝试是让StoredProcedureA调用StoredProcedureB调用StoredProcedureC调用StoredProcedureD来查询视图。

如果不行，让存储过程调用一个存储过程，调用一个UDF，调用一个UDF，调用一个存储过程，调用一个UDF来查询视图。

综上所述，以下代码在QA中运行得很快，但在存储过程中运行得很慢:

原文:

--Runs fine outside of a stored procedure
SELECT *
FROM Report_OpenerTest
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank

sp_executesql:

--Runs fine outside of a stored procedure
DECLARE @SQLString NVARCHAR(500)
SET @SQLString = N'SELECT *
FROM Report_OpenerTest
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank'

EXECUTE sp_executesql @SQLString,
        N'@SessionGUID uniqueidentifier',
        @SessionGUID

EXEC (@sql):

--Runs fine outside of a stored procedure
DECLARE @sql NVARCHAR(500)
SET @sql = N'SELECT *
FROM Report_OpenerTest
WHERE SessionGUID = '''+CAST(@SessionGUID AS varchar(50))+'''
ORDER BY CurrencyTypeOrder, Rank'

EXEC(@sql)

执行计划

好办法:

      |--Sort(ORDER BY:([Expr1020] ASC, [Currencies].[Rank] ASC))
           |--Compute Scalar(DEFINE:([Expr1020]=If ([Currencies].[CurrencyType]='ctCanadianCash') then 1 else If ([Currencies].[CurrencyType]='ctMiscellaneous') then 2 else If ([Currencies].[CurrencyType]='ctTokens') then 3 else If ([Currencies].[CurrencyType]
                |--Nested Loops(Left Outer Join, OUTER REFERENCES:([Openers].[OpenerGUID]))
                     |--Filter(WHERE:((([Currencies].[IsActive]<>0 AND [Currencies].[OnOpener]<>0) AND ((((((([Currencies].[CurrencyType]='ctUSCoin' OR [Currencies].[CurrencyType]='ctMiscellaneousUS') OR [Currencies].[CurrencyType]='ctUSCash') OR [Currencies].
                     |    |--Nested Loops(Left Outer Join, OUTER REFERENCES:([Currencies].[CurrencyGUID], [Openers].[OpenerGUID]) WITH PREFETCH)
                     |         |--Nested Loops(Left Outer Join)
                     |         |    |--Bookmark Lookup(BOOKMARK:([Bmk1016]), OBJECT:([GrobManagementSystemLive].[dbo].[Windows]))
                     |         |    |    |--Nested Loops(Inner Join, OUTER REFERENCES:([Openers].[WindowGUID]))
                     |         |    |         |--Bookmark Lookup(BOOKMARK:([Bmk1014]), OBJECT:([GrobManagementSystemLive].[dbo].[Openers]))
                     |         |    |         |    |--Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[Openers].[IX_Openers_SessionGUID]), SEEK:([Openers].[SessionGUID]=[@SessionGUID]) ORDERED FORWARD)
                     |         |    |         |--Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[Windows].[IX_Windows]), SEEK:([Windows].[WindowGUID]=[Openers].[WindowGUID]) ORDERED FORWARD)
                     |         |    |--Clustered Index Scan(OBJECT:([GrobManagementSystemLive].[dbo].[Currencies].[IX_Currencies_CurrencyType]))
                     |         |--Clustered Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[OpenerDetails].[IX_OpenerDetails_OpenerGUIDCurrencyGUID]), SEEK:([OpenerDetails].[OpenerGUID]=[Openers].[OpenerGUID] AND [OpenerDetails].[CurrencyGUID]=[Currenc
                     |--Hash Match(Cache, HASH:([Openers].[OpenerGUID]), RESIDUAL:([Openers].[OpenerGUID]=[Openers].[OpenerGUID]))
                          |--Stream Aggregate(DEFINE:([Expr1006]=SUM(If (((([Currencies].[CurrencyType]='ctMiscellaneous' OR [Currencies].[CurrencyType]='ctTokens') OR [Currencies].[CurrencyType]='ctChips') OR [Currencies].[CurrencyType]='ctCanadianCoin') OR [
                               |--Nested Loops(Inner Join, OUTER REFERENCES:([OpenerDetails].[CurrencyGUID]) WITH PREFETCH)
                                    |--Nested Loops(Inner Join)
                                    |    |--Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[Openers].[IX_Openers_OneOpenerPerSession]), SEEK:([Openers].[OpenerGUID]=[Openers].[OpenerGUID]) ORDERED FORWARD)
                                    |    |--Clustered Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[OpenerDetails].[IX_OpenerDetails_OpenerGUIDCurrencyGUID]), SEEK:([OpenerDetails].[OpenerGUID]=[Openers].[OpenerGUID]) ORDERED FORWARD)
                                    |--Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[Currencies].[PK_Currencies_CurrencyGUID]), SEEK:([Currencies].[CurrencyGUID]=[OpenerDetails].[CurrencyGUID]) ORDERED FORWARD)

糟糕的计划

       |--Sort(ORDER BY:([Expr1020] ASC, [Currencies].[Rank] ASC))
            |--Compute Scalar(DEFINE:([Expr1020]=If ([Currencies].[CurrencyType]='ctCanadianCash') then 1 else If ([Currencies].[CurrencyType]='ctMiscellaneous') then 2 else If ([Currencies].[CurrencyType]='ctTokens') then 3 else If ([Currencies].[Currency
                 |--Nested Loops(Left Outer Join, OUTER REFERENCES:([Openers].[OpenerGUID]))
                      |--Filter(WHERE:((([Currencies].[IsActive]<>0 AND [Currencies].[OnOpener]<>0) AND ((((((([Currencies].[CurrencyType]='ctUSCoin' OR [Currencies].[CurrencyType]='ctMiscellaneousUS') OR [Currencies].[CurrencyType]='ctUSCash') OR [Currenc
                      |    |--Nested Loops(Left Outer Join, OUTER REFERENCES:([Currencies].[CurrencyGUID], [Openers].[OpenerGUID]) WITH PREFETCH)
                      |         |--Filter(WHERE:([Openers].[SessionGUID]=[@SessionGUID]))
                      |         |    |--Concatenation
                      |         |         |--Nested Loops(Left Outer Join)
                      |         |         |    |--Table Spool
                      |         |         |    |    |--Hash Match(Inner Join, HASH:([Windows].[WindowGUID])=([Openers].[WindowGUID]), RESIDUAL:([Windows].[WindowGUID]=[Openers].[WindowGUID]))
                      |         |         |    |         |--Clustered Index Scan(OBJECT:([GrobManagementSystemLive].[dbo].[Windows].[IX_Windows_CageGUID]))
                      |         |         |    |         |--Table Scan(OBJECT:([GrobManagementSystemLive].[dbo].[Openers]))
                      |         |         |    |--Table Spool
                      |         |         |         |--Clustered Index Scan(OBJECT:([GrobManagementSystemLive].[dbo].[Currencies].[IX_Currencies_CurrencyType]))
                      |         |         |--Compute Scalar(DEFINE:([Openers].[OpenerGUID]=NULL, [Openers].[SessionGUID]=NULL, [Windows].[UseChipDenominations]=NULL))
                      |         |              |--Nested Loops(Left Anti Semi Join)
                      |         |                   |--Clustered Index Scan(OBJECT:([GrobManagementSystemLive].[dbo].[Currencies].[IX_Currencies_CurrencyType]))
                      |         |                   |--Row Count Spool
                      |         |                        |--Table Spool
                      |         |--Clustered Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[OpenerDetails].[IX_OpenerDetails_OpenerGUIDCurrencyGUID]), SEEK:([OpenerDetails].[OpenerGUID]=[Openers].[OpenerGUID] AND [OpenerDetails].[CurrencyGUID]=[Cu
                      |--Hash Match(Cache, HASH:([Openers].[OpenerGUID]), RESIDUAL:([Openers].[OpenerGUID]=[Openers].[OpenerGUID]))
                           |--Stream Aggregate(DEFINE:([Expr1006]=SUM([partialagg1034]), [Expr1007]=SUM([partialagg1035]), [Expr1008]=SUM([partialagg1036]), [Expr1009]=SUM([partialagg1037]), [Expr1010]=SUM([partialagg1038]), [Expr1011]=SUM([partialagg1039]
                                |--Nested Loops(Inner Join)
                                     |--Stream Aggregate(DEFINE:([partialagg1034]=SUM(If (((([Currencies].[CurrencyType]='ctMiscellaneous' OR [Currencies].[CurrencyType]='ctTokens') OR [Currencies].[CurrencyType]='ctChips') OR [Currencies].[CurrencyType]='
                                     |    |--Nested Loops(Inner Join, OUTER REFERENCES:([OpenerDetails].[CurrencyGUID]) WITH PREFETCH)
                                     |         |--Clustered Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[OpenerDetails].[IX_OpenerDetails_OpenerGUIDCurrencyGUID]), SEEK:([OpenerDetails].[OpenerGUID]=[Openers].[OpenerGUID]) ORDERED FORWARD)
                                     |         |--Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[Currencies].[PK_Currencies_CurrencyGUID]), SEEK:([Currencies].[CurrencyGUID]=[OpenerDetails].[CurrencyGUID]) ORDERED FORWARD)
                                     |--Index Seek(OBJECT:([GrobManagementSystemLive].[dbo].[Openers].[IX_Openers_OneOpenerPerSession]), SEEK:([Openers].[OpenerGUID]=[Openers].[OpenerGUID]) ORDERED FORWARD)

坏的是，它急切地要处理600万行数据;另一个不是。

注意:这不是一个关于调优查询的问题。我有一个快速运行的查询。我只是想让SQL Server从存储过程中快速运行。

当前回答

我也面临着同样的问题&这篇文章对我很有帮助，但没有一个帖子的答案解决了我的具体问题。我想把这个对我有用的解决方法贴出来，希望它能帮助到其他人。

https://stackoverflow.com/a/24016676/814299

在查询的最后，添加OPTION (OPTIMIZE FOR (@now UNKNOWN))

2017-05-31 15:58:13

其他回答

我有另一个主意。如果你创建这个基于表的函数:

CREATE FUNCTION tbfSelectFromView
(   
    -- Add the parameters for the function here
    @SessionGUID UNIQUEIDENTIFIER
)
RETURNS TABLE 
AS
RETURN 
(
    SELECT *
    FROM Report_Opener
    WHERE SessionGUID = @SessionGUID
    ORDER BY CurrencyTypeOrder, Rank
)
GO

然后使用下面的语句从它中选择(甚至把它放在你的SP中):

SELECT *
FROM tbfSelectFromView(@SessionGUID)

看起来发生的事情(每个人都已经评论过了)是SQL Server只是在某个地方做了一个错误的假设，也许这将迫使它纠正这个假设。我不想多走一步，但我不确定还有什么原因。

2009-01-13 23:15:57

您尝试过重新构建Report_Opener表上的统计数据和/或索引吗?如果统计数据仍然显示数据库首次启动时的数据，那么SP的所有重新遵从都将毫无价值。

初始查询本身工作得很快，因为优化器可以看到参数永远不会为空。在SP的情况下，优化器不能确保参数永远不会为空。

2009-01-13 21:57:54

这可能听起来很愚蠢，而且从SessionGUID的名称来看似乎很明显，但是列是Report_Opener上的唯一标识符吗?如果不是，您可能想要尝试将其强制转换为正确的类型，并给它一个机会或将变量声明为正确的类型。

作为sproc的一部分创建的计划可能不直观地工作，并在一个大表上执行内部强制转换。

2015-07-15 16:45:43

虽然我通常反对它(尽管在这种情况下，您似乎有一个真正的理由)，但您是否尝试过在SP版本的查询上提供任何查询提示?如果SQL Server在这两个实例中准备了不同的执行计划，您是否可以使用一个提示告诉它使用哪个索引，以便计划与第一个匹配?

一些例子，你可以点击这里。

编辑:如果您可以在这里发布您的查询计划，也许我们可以确定计划之间的一些差异。

第二:将链接更新为特定于SQL-2000。你必须向下滚动，但有第二个标题为“表格提示”，这就是你要找的。

第三:“坏”查询似乎忽略了“Openers”表上的[IX_Openers_SessionGUID] -添加一个INDEX提示来强制它使用该索引是否会改变事情?

2009-01-13 21:57:14

我发现了问题，下面是存储过程的慢版本和快版本的脚本:

dbo.ViewOpener__RenamedForCruachan__Slow.PRC

SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS OFF 
GO

CREATE PROCEDURE dbo.ViewOpener_RenamedForCruachan_Slow
    @SessionGUID uniqueidentifier
AS

SELECT *
FROM Report_Opener_RenamedForCruachan
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank
GO

SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO

dbo.ViewOpener__RenamedForCruachan__Fast.PRC

SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO

CREATE PROCEDURE dbo.ViewOpener_RenamedForCruachan_Fast
    @SessionGUID uniqueidentifier 
AS

SELECT *
FROM Report_Opener_RenamedForCruachan
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank
GO

SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO

如果你没有发现其中的差别，我不怪你。区别根本不在存储过程中。将一个快速的0.5成本查询转换为一个执行600万行的即时线轴查询的差异:

慢:设置ANSI_NULLS关闭

快速:设置ANSI_NULLS为ON

这个答案也可能是有意义的，因为视图确实有一个join子句，它说:

(table.column IS NOT NULL)

这里涉及到一些null。

返回到Query Analizer并运行，进一步证明了这一解释

SET ANSI_NULLS OFF

.

DECLARE @SessionGUID uniqueidentifier
SET @SessionGUID = 'BCBA333C-B6A1-4155-9833-C495F22EA908'

.

SELECT *
FROM Report_Opener_RenamedForCruachan
WHERE SessionGUID = @SessionGUID
ORDER BY CurrencyTypeOrder, Rank

查询很慢。

因此，问题并不是因为查询是从存储过程中运行的。问题是Enterprise Manager的连接默认选项是ANSI_NULLS off，而不是QA的默认选项ANSI_NULLS on。

微软在KB296769中承认了这一事实(错误:不能使用SQL企业管理器创建包含链接服务器对象的存储过程)。解决方法是在存储过程对话框中包含ANSI_NULLS选项:

Set ANSI_NULLS ON
Go
Create Proc spXXXX as
....
2009-01-14 15:27:01

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