极慢速执行SELECT

Question

我有一个表与7526511个记录，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 

执行计划是这样的：

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) 

当我运行查询它不在任何合理的时间范围内完成。我让查询运行了5分钟以上，但它仍然没有返回我要求的单个行。这种类型的慢SELECT性能对数据库有其他影响，例如难以摆脱我们不再需要的行。

你知道我的瓶颈可能在哪里吗？ 98 gig数据库及其日志在SQL Server 2008上运行的4磁盘RAID 10上，驱动器上有超过100个可用空间。

Answer 1

您是否检查过您是否遇到阻塞问题？

Answer 2

创建具有所需结构的另一个表并复制/“泵”数据，然后删除旧表并重新命名新表？您可能需要在“批次”中针对特定ID范围执行此操作：

INSERT INTO LogSearches_new ... SELECT * FROM LogSearches WHERE ID BETWEEN 1 AND 999999