requêtes lentes après l'exécution DBCC DROPCLEANBUFFERS

J'ai 2 tables Called "Users(60,0000 records),UserBasicInfo(60,0000 records)", la table des utilisateurs ont un index ordonné en clusters sur la table UserSid colonne.Le UserBasicInfo un point FK UserSid à la table des utilisateurs colonne UserSid et ont non clusterisé sur une colonne UpdateTime,UsersID.requêtes lentes après l'exécution DBCC DROPCLEANBUFFERS

CREATE TABLE [dbo].[Users](
    [UsersID] [int] IDENTITY(100000,1) NOT NULL, 
    [LoginUsersName] [nvarchar](50) NOT NULL, 
    [LoginUsersPwd] [nvarchar](50) NOT NULL, 
    [Email] [nvarchar](80) NOT NULL, 
    [IsEnable] [int] NOT NULL, 
    [CreateTime] [datetime] NOT NULL, 
    [LastLoginTime] [datetime] NOT NULL, 
    [LastLoginIp] [nvarchar](50) NOT NULL, 
    [UpdateTime] [datetime] NOT NULL, 
CONSTRAINT [PK_Users] PRIMARY KEY CLUSTERED 
(
    [UsersID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 


CREATE TABLE [dbo].[UserBasicInfo](
    [UserBaicInfoID] [int] IDENTITY(1,1) NOT NULL, 
    [UsersID] [int] NOT NULL, 
    [ResumePoints] [nvarchar](50) NOT NULL, 
    [IsChineseOrEnglish] [int] NOT NULL, 
    [UserName] [nvarchar](50) NOT NULL, 
    [Sex] [int] NOT NULL, 
    [Height] [int] NOT NULL, 
    [Birthday] [datetime] NOT NULL, 
    [Age] [int] NOT NULL, 
    [IDCard] [nvarchar](50) NOT NULL, 
    [IsMarryed] [int] NOT NULL, 
    [NativePlace] [nvarchar](50) NOT NULL, 
    [PoliticalStatus] [int] NOT NULL, 
    [CurrentAddress] [nvarchar](50) NOT NULL, 
    [CurrentAddressDetail] [nvarchar](50) NOT NULL, 
    [WorkExperience] [int] NOT NULL, 
    [HighestEducation] [int] NOT NULL, 
    [LogoPath] [nvarchar](200) NULL, 
    [MobilePhone] [nvarchar](50) NOT NULL, 
    [Phone] [nvarchar](50) NULL, 
    [QQ] [nvarchar](50) NULL, 
    [Blog] [nvarchar](300) NULL, 
    [MicroBlog] [nvarchar](300) NULL, 
    [PositionDesired] [nvarchar](100) NOT NULL, 
    [IndustrySmallClass] [nvarchar](100) NULL, 
    [PositionName] [nvarchar](100) NOT NULL, 
    [PositionType] [int] NOT NULL, 
    [WorkAddressLarge] [int] NOT NULL, 
    [WorkAddressSmall] [nvarchar](200) NOT NULL, 
    [WorkAddressSmallText] [nvarchar](100) NOT NULL, 
    [Salary] [int] NOT NULL, 
    [HousingRequirement] [int] NOT NULL, 
    [ToWorkTime] [int] NOT NULL, 
    [ResumeState] [int] NOT NULL, 
    [IsSystemAdd] [int] NOT NULL, 
    [CreateTime] [datetime] NOT NULL, 
    [UpdateTime] [datetime] NOT NULL, 
    [RefreshDateTime] [datetime] NOT NULL, 
    [RefreshTime] [int] NOT NULL, 
    [TotalTime] [int] NOT NULL, 
CONSTRAINT [PK_UserBasicInfo] PRIMARY KEY CLUSTERED 
(
    [UserBaicInfoID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 
ALTER TABLE [dbo].[UserBasicInfo] WITH CHECK ADD CONSTRAINT [FK_UserBasicInfo_Users] FOREIGN KEY([UsersID]) 
REFERENCES [dbo].[Users] ([UsersID])

Mais exécuter ci-dessous lent:

DBCC DROPCLEANBUFFERS 
DBCC FREEPROCCACHE 
SELECT TOP 100 * FROM Users U INNER JOIN UserBasicInfo UB ON UB.UsersID=U.UsersID ORDER BY UB.UpdateTime DESC 

SQL Server Execution Times: 
    CPU time = 16 ms, elapsed time = 3568 ms.

enter image description here Ensuite, exécutez ci-dessous rapide:

SELECT TOP 100 * FROM Users U INNER JOIN UserBasicInfo UB ON UB.UsersID=U.UsersID ORDER BY UB.UpdateTime DESC 

SQL Server Execution Times: 
    CPU time = 0 ms, elapsed time = 163 ms.

enter image description here

Il est normal?

Source

2013-06-27 user441222

Oui, il est normal

Vos 2 commandes DBCC AHVE supprimés plans de requête et les données mises en cache. Les données doivent à nouveau être lues à partir du disque, ce qui est probablement la surcharge principale.

Si vous ajoutez SET STATISTICS IO ON vous verrez plus « page physique lit » et « lecture anticipée lit » après la DBCC sous forme de données est chargé à partir du disque

Je presque jamais les cours. Pour en savoir plus, reportez-vous à ces questions dba.se

Source

2013-06-27 08:39:36 gbn

Merci vous variez beaucoup! – user441222

requêtes lentes après l'exécution DBCC DROPCLEANBUFFERS

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