我有一個表與7526511個記錄,定義如下:極慢速執行SELECT
/****** 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
執行計劃是這樣的:
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)
當我運行查詢它不在任何合理的時間範圍內完成。我讓查詢運行了5分鐘以上,但它仍然沒有返回我要求的單個行。這種類型的慢SELECT性能對數據庫有其他影響,例如難以擺脫我們不再需要的行。
你知道我的瓶頸可能在哪裏嗎? 98 gig數據庫及其日誌在SQL Server 2008上運行的4磁盤RAID 10上,驅動器上有超過100個可用空間。
您確定您選擇的行沒有被另一個進程鎖定的行/頁面/數據庫阻止?嘗試添加(NoLock)到您的查詢結束,看看是否有幫助 – u07ch 2009-12-07 14:35:32
它使用時返回(NOLOCK) – 2009-12-07 14:37:57
它確實返回NOLOCK。看起來我做了一個noob錯誤,因爲我一直在處理這個表。該死的。長。它讓我永遠清除我們不再需要的行。 – 2009-12-07 14:48:53