Question

我对SQL Server 2008 R2上的存储过程有一个非常奇怪的问题。有时，每个月大约一次，我有一个变得非常慢的过程，运行大约需要6秒而不是几毫秒。但是，如果我只是重新编译它，而不改变任何东西，它会再次快速运行。它不会发生在所有存储过程中，只有一个（服务器上有几百个）。

我的猜测是sp编译时，它被缓存，每次调用它时都会重用这个缓存，而且这个缓存版本由于某种原因而被破坏。

我希望也许有些人已经遇到过这种问题，或者至少可以指出我正确的方向，比如SQL Server或IIS的哪些配置会影响存储过程缓存？

以下是代码：

USE [MyBaseName]
GO
/****** Object:  StoredProcedure [dbo].[Publication_getByCriteria]    Script Date: 05/29/2013 12:11:07 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[Publication_getByCriteria]
    @id_sousTheme As int = null,
    @id_theme As int = null,
    @nbPubli As int = 1000000,
    @bActuSite As bit = null,
    @bActuPerso As bit = null,
    @bActuNewsletter As bit = null,
    @bActuChronique As bit = null,
    @bActuVideo As bit = null,
    @bActuVideoBuzz As bit = null,
    @bActuOpportunite As bit = null,
    @id_contact As int = null,
    @bOnlyPublished As bit = 0,
    @bOnlyForHomePage as bit = 0,
    @id_contactForTheme As int = null,
    @id_newsletter As int = null,
    @ID_ActuChronique As int = null,
    @sMotClef As varchar(500) = null,
    @sMotClefForFullText as varchar(500) = '""',
    @dtPublication As datetime = null,  
    @bParlonsFinance As bit = null,
    @bPartenaires as bit = null,
    @bUne As bit = null,
    @bEditoParlonsFinance As bit = null,
    @bEditoQuestionFonds as bit = null,
    @dtDebPublication As datetime = null,
    @dtFinPublication As datetime = null,
    @bOnlyActuWithDroitReponse As bit = 0,
    @bActuDroitReponse As bit = null
AS
BEGIN
    SET NOCOUNT ON;

    DECLARE @dtNow As datetime
    SET @dtNow = GETDATE()

    SELECT TOP (@nbPubli) p.id_publication, p.sTitre, p.sTexte, p.sTexteHTML, p.dtPublication, p.id_linkedDroitReponse,
        si.id_actusite, pe.id_actuPerso, ne.id_actuNewsletter, ac.id_actuChronique, av.id_actuVideo, ap.id_actuOpportunite, ad.id_actuDroitReponse,
        c.ID_Contact, c.sPhotoCarre, NULL As sTypePubli, n.id_newsletter, 
        dbo.Publication_get1Theme(p.id_publication) As theme,
        CAST(CASE WHEN ad.id_actuDroitReponse IS NULL THEN 0 ELSE 1 END As bit) As bIsDroitReponse,
        coalesce(Personne.sNom, Societe.sNom) as sNom, Personne.sPrenom
    FROM Publication p
        LEFT OUTER JOIN ActuSite si ON p.id_publication = si.id_publication
        LEFT OUTER JOIN ActuPerso pe ON p.id_publication = pe.id_publication
        LEFT OUTER JOIN ActuNewsletter ne ON p.id_publication = ne.id_publication
        LEFT OUTER JOIN ActuChronique ac ON p.id_publication = ac.id_publication
        LEFT OUTER JOIN ActuVideo av ON p.id_publication = av.id_publication
        LEFT OUTER JOIN ActuOpportunite ap ON p.id_publication = ap.id_publication
        LEFT OUTER JOIN ActuDroitReponse ad ON p.id_publication = ad.id_publication
        LEFT OUTER JOIN Contact c ON p.id_contact = c.ID_Contact
        LEFT OUTER JOIN Personne ON Personne.id_contact = c.id_contact
        LEFT OUTER JOIN Societe ON Societe.id_contact = c.id_contact
        LEFT OUTER JOIN Newsletter n ON ne.id_actuNewsletter = n.id_actuNewsletter
    WHERE p.bSupp = 0
    AND (@bOnlyPublished = 0 Or (@bOnlyPublished = 1 AND p.dtPublication IS NOT NULL AND p.dtPublication < @dtNow))
    AND (@id_sousTheme IS NULL Or p.id_publication IN(SELECT id_publication FROM PubliSousTheme WHERE id_soustheme = @id_sousTheme))
    AND (@id_theme IS NULL Or p.id_publication IN(SELECT id_publication FROM PubliTheme WHERE id_theme = @id_theme))
    AND ((@bActuSite = 1 AND si.id_actusite IS NOT NULL)
            OR (@bActuPerso = 1 AND pe.id_actuPerso IS NOT NULL)
            OR (@bActuNewsletter = 1 AND ne.id_actuNewsletter IS NOT NULL)
            OR (@bActuChronique = 1 AND ac.id_actuChronique IS NOT NULL)
            OR (@bActuVideo = 1 AND av.id_actuVideo IS NOT NULL)
            OR (@bActuVideoBuzz = 1 AND av.id_actuVideo IS NOT NULL and coalesce(av.sBuzz, '') <> '' )
            OR (@bActuOpportunite = 1 AND ap.id_actuOpportunite IS NOT NULL)
            OR (@bActuDroitReponse = 1 AND ad.id_actuDroitReponse IS NOT NULL))
    AND (@id_contact IS NULL Or p.id_contact = @id_contact)
    AND (@id_contactForTheme IS NULL Or 
            (p.id_publication IN(SELECT id_publication FROM PubliSousTheme 
                WHERE id_soustheme IN(SELECT id_soustheme FROM ContactSousTheme WHERE id_contact = @id_contactForTheme)))
            Or (p.id_publication IN(SELECT id_publication FROM PubliTheme 
                WHERE id_theme IN(SELECT id_theme FROM ContactTheme WHERE id_contact = @id_contactForTheme)))
            )
    AND (@ID_ActuChronique is NULL or id_actuChronique = @ID_ActuChronique)
    AND (@id_newsletter IS NULL Or p.id_publication IN(SELECT id_publication FROM ListActuNewsletter WHERE id_newsletter = @id_newsletter))
    AND (@sMotClef IS NULL 
        or contains((p.sTexte, p.sTitre), @sMotClefForFullText)
        Or Personne.sNom LIKE '%' + @sMotClef + '%' COLLATE Latin1_General_CI_AI
        Or Personne.sPrenom LIKE '%' + @sMotClef + '%' COLLATE Latin1_General_CI_AI
        Or Societe.sNom LIKE '%' + @sMotClef + '%' COLLATE Latin1_General_CI_AI
        )
    AND (@dtPublication IS NULL Or p.dtPublication >= @dtPublication)
    AND (
        @bParlonsFinance IS NULL Or
        (@bParlonsFinance = 0 AND p.id_publication NOT IN(SELECT id_publication FROM PubliTheme 
                WHERE id_theme IN(SELECT id_theme FROM Theme WHERE bParlonsFinance = 1)))
        Or (@bParlonsFinance = 1 AND p.id_publication IN(SELECT id_publication FROM PubliTheme 
                WHERE id_theme IN(SELECT id_theme FROM Theme WHERE bParlonsFinance = 1))))
    AND (
        @bPartenaires IS NULL Or
        (@bPartenaires = 0 AND p.id_publication NOT IN(SELECT id_publication FROM PubliTheme 
                WHERE id_theme IN(SELECT id_theme FROM Theme WHERE 0 = 1)))
        Or (@bPartenaires = 1 AND p.id_publication IN(SELECT id_publication FROM PubliTheme 
                WHERE id_theme IN(SELECT id_theme FROM Theme WHERE 0 = 1))))
    AND (
        @bUne IS NULL
        Or p.bUne = @bUne)
    AND (@bEditoParlonsFinance IS NULL
        Or p.bEditoParlonsFinance = @bEditoParlonsFinance)
        AND (@bEditoQuestionFonds IS NULL
        Or p.bEditoQuestionFonds = @bEditoQuestionFonds)
    AND (@dtDebPublication IS NULL Or p.dtPublication >= @dtDebPublication)
    AND (@dtFinPublication IS NULL Or p.dtPublication <= @dtFinPublication)
    AND (@bOnlyActuWithDroitReponse = 0 Or (@bOnlyActuWithDroitReponse = 1 AND p.id_linkedDroitReponse IS NOT NULL))
    and (@bOnlyForHomePage = 0 or (@bOnlyForHomePage = 1 and ac.bHomePage = 1))
    ORDER BY coalesce(p.dtPublication, p.dtCreate) DESC, p.id_publication DESC
END

Answer 1

首次编译存储过程时，其执行计划会被缓存。

如果sproc具有参数，其定义可以显着改变包含的查询的执行计划（例如索引扫描与搜索），则存储过程的缓存计划可能不适用于所有参数定义。

避免这种情况的一种方法是在RECOMPILE语句中加入CREATE PROCEDURE子句。

示例：

CREATE PROCEDURE dbo.mySpro
@myParam
WITH RECOMPILE
AS
BEGIN
 -- INSERT WORKLOAD HERE
END
GO

通过这样做，每次调用过程时都会生成一个新计划。如果recompile time＆lt; time lost by its using the wrong cached plan，这值得使用WITH RECOMPILE。在您的情况下，它还将节省您每次发现它缓慢执行时手动重新编译此过程所需的时间/计划。

Answer 2

对于具有那么多参数的存储过程，最好在查询结束时添加OPTION(OPTIMIZE FOR UNKNOWN)，以告诉编译器不要优化特定参数的执行计划。

SQL Server第一次运行存储过程时所执行的操作是优化传递给它的参数的执行计划。这是在称为Parameter Sniffing的过程中完成的。

通常，执行计划由SQL Server缓存，因此SQL Server不必每次都为同一查询重新编译。下次运行该过程时，SQL Server将重新使用其中的查询的执行计划...但是，如果使用不同的参数调用存储过程，则执行计划可能完全没有效率。

添加我提到的选项将告诉SQL编译器不应针对特定的参数优化执行计划，而是针对传递给的任何参数。存储过程。来自documentation：

未知的优化

指示查询优化器在编译和优化查询时使用统计数据而不是所有局部变量的初始值，包括使用强制参数化创建的参数。

@sion_corn的回答建议将WITH RECOMPILE添加到存储过程定义中，但这会强制每次执行存储过程时重新编译整个语句。如果经常调用该过程，这可能会产生不可接受的开销。

重新编译后，存储过程快速运行

2 个答案: