I have a table with with 7,526,511 records with the following definition:
/****** 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
The execution plan looks like this:
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)
When I run the query it doesn’t finish in any sort of reasonable time frame. I’ve let the query run for over 5 minutes, and it still didn’t return the single row I asked for. This type of slow SELECT performance is having other effects on the database, such as making it difficult to get rid of rows we no longer need.
Do you have an idea where my bottleneck might be? The 98 gig database and its logs are running on SQL Server 2008 on a 4-disk RAID 10 with over 100 gigs of free space on the drives.
Have you checked to see if you are having a blocking issue?