执行选择非常慢

我有一个包含7526511条记录的表,定义如下:

/****** Object:  Table [dbo].[LogSearches]    Script Date: 12/07/2009 09:23:14 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[LogSearches](
    [ID] [numeric](18, 0) IDENTITY(1,1) NOT NULL,
    [Acct_ID] [int] NULL,
    [RecordCount] [int] NOT NULL,
    [PageNumber] [int] NOT NULL,
    [Site_ID] [int] NOT NULL,
    [SearchAPI] [bit] NOT NULL,
    [FormSearch] [bit] NOT NULL,
    [IPAddress] [varchar](15) NOT NULL,
    [Domain] [nvarchar](150) NOT NULL,
    [ScriptName] [nvarchar](500) NOT NULL,
    [QueryString] [varchar](max) NULL,
    [Referer] [nvarchar](1024) NOT NULL,
    [SearchString] [nvarchar](max) NOT NULL,
    [UserAgent] [nvarchar](2048) NULL,
    [Processed] [datetime] NOT NULL,
    [Created] [datetime] NOT NULL,
    [IntegerIP] [int] NULL,
 CONSTRAINT [PK_LogSearches] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[LogSearches] ADD  CONSTRAINT [DF_LogSearches_Processed]  DEFAULT (getdate()) FOR [Processed]
GO

ALTER TABLE [dbo].[LogSearches] ADD  CONSTRAINT [DF_LogSearches_Created]  DEFAULT (getdate()) FOR [Created]
GO

执行计划如下:

StmtText                                                                                 StmtId      NodeId      Parent      PhysicalOp                     LogicalOp                      Argument                                                 DefinedValues                                                                                                                                                                                                                                                    EstimateRows  EstimateIO    EstimateCPU   AvgRowSize  TotalSubtreeCost OutputList                                                                                                                                                                                                                                                       Warnings Type                                                             Parallel EstimateExecutions
---------------------------------------------------------------------------------------- ----------- ----------- ----------- ------------------------------ ------------------------------ -------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ------------- ------------- ------------- ----------- ---------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -------- ---------------------------------------------------------------- -------- ------------------
SELECT TOP 1 * FROM LogSearches                                                          1           1           0           NULL                           NULL                           1                                                        NULL                                                                                                                                                                                                                                                             1             NULL          NULL          NULL        0.0032832        NULL                                                                                                                                                                                                                                                             NULL     SELECT                                                           0        NULL
  |--Top(TOP EXPRESSION:((1)))                                                           1           2           1           Top                            Top                            TOP EXPRESSION:((1))                                     NULL                                                                                                                                                                                                                                                             1             0             1E-07         11848       0.0032832        [LOALogs].[dbo].[LogSearches].[ID], [LOALogs].[dbo].[LogSearches].[Acct_ID], [LOALogs].[dbo].[LogSearches].[RecordCount], [LOALogs].[dbo].[LogSearches].[PageNumber], [LOALogs].[dbo].[LogSearches].[Site_ID], [LOALogs].[dbo].[LogSearches].[SearchAPI], [LOALo NULL     PLAN_ROW                                                         0        1
       |--Clustered Index Scan(OBJECT:([LOALogs].[dbo].[LogSearches].[PK_LogSearches]))  1           3           2           Clustered Index Scan           Clustered Index Scan           OBJECT:([LOALogs].[dbo].[LogSearches].[PK_LogSearches])  [LOALogs].[dbo].[LogSearches].[ID], [LOALogs].[dbo].[LogSearches].[Acct_ID], [LOALogs].[dbo].[LogSearches].[RecordCount], [LOALogs].[dbo].[LogSearches].[PageNumber], [LOALogs].[dbo].[LogSearches].[Site_ID], [LOALogs].[dbo].[LogSearches].[SearchAPI], [LOALo 1             2956.71       8.279319      11848       0.0032831        [LOALogs].[dbo].[LogSearches].[ID], [LOALogs].[dbo].[LogSearches].[Acct_ID], [LOALogs].[dbo].[LogSearches].[RecordCount], [LOALogs].[dbo].[LogSearches].[PageNumber], [LOALogs].[dbo].[LogSearches].[Site_ID], [LOALogs].[dbo].[LogSearches].[SearchAPI], [LOALo NULL     PLAN_ROW                                                         0        1

(3 row(s) affected)

当我运行查询时,它不会在任何合理的时间范围内完成。我让查询运行了超过5分钟,但它仍然没有返回我请求的单行。这种类型的慢选择性能对数据库有其他影响,例如,很难除去不再需要的行。

你知道我的瓶颈在哪里吗?98 Gig数据库及其日志运行在SQL Server 2008上的4磁盘RAID 10上,驱动器上有超过100 Gig的可用空间。