我有一个 CTE 查询似乎会导致大量逻辑读取(或者它可能不会)。我已经运行了 SQL Server Profiler 跟踪,并且此查询似乎一直是运行时间最长的查询之一。(每次点击页面都会调用它)
基本上我想知道我的 CTE 是否正确优化,或者可以改进。
SET STATISTICS IO ON;
GO
;WITH cte (PageId, PageTitle, PageType, PageHeadingId, ParentPage, InNavigation, OrgLevel, SortKey, PageOrder, PathLength, PathName, Active) AS
(
SELECT
PageId,
PageTitle,
PageType,
PageHeadingId,
ParentPage,
InNavigation,
0,
CAST (PageOrder AS VARBINARY(200)),
PageOrder,
0 AS PathLength,
CAST('' as varchar(300)) AS PathName,
Active
FROM dbo.ContentPage
WHERE ParentPage = 0
AND InNavigation = 1
UNION ALL
SELECT
b.PageId,
b.PageTitle,
b.PageType,
b.PageHeadingId,
b.ParentPage,
b.InNavigation,
cte.OrgLevel+1,
CAST(cte.SortKey + CAST (b.PageOrder AS BINARY(4)) AS VARBINARY(200)),
b.PageOrder,
((cte.OrgLevel+1) + len('....'+b.PageTitle)) as PathLength,
CAST ((cte.PathName+'....') AS VARCHAR(300)) AS PathName,
b.Active
FROM dbo.ContentPage b
JOIN cte ON b.ParentPage = cte.PageId
WHERE b.PageType NOT IN (4, 8, 11, 12, 14)
-- Remove specific page types from the ContentPage table
)
SELECT *, (PathName+PageTitle) AS Hierarchy
FROM cte WHERE InNavigation = 1
ORDER BY SortKey--, PageOrder
SET STATISTICS IO OFF;
GO
如果我离开这条线:
WHERE b.PageType NOT IN (4, 8, 11, 12, 14)
出,然后逻辑读取的数量从〜8500跳到〜13000
(查询所做的是在 ASP.NET 中构建下拉菜单层次结构)如果逻辑读取没问题,那么我假设我必须想出另一种方法来缓存/存储这个菜单(更新 2 或一周3次)
谢谢
ContentPage 的表结构
CREATE TABLE [dbo].[ContentPage](
[PageId] [int] IDENTITY(1,1) NOT NULL,
[PageTitle] [nvarchar](150) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
[PageQuote] [nvarchar](400) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[MetaKeywords] [nvarchar](200) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[MetaDescription] [ntext] COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[PageContent] [ntext] COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[Active] [bit] NOT NULL CONSTRAINT [DF_ContentPage_Active] DEFAULT ((0)),
[InNavigation] [bit] NOT NULL CONSTRAINT [DF_ContentPage_InNavigation] DEFAULT ((1)),
[PageOrder] [int] NOT NULL CONSTRAINT [DF_ContentPage_PageOrder] DEFAULT ((50)),
[ParentPage] [int] NOT NULL CONSTRAINT [DF_ContentPage_ParentPage] DEFAULT ((0)),
[PageType] [int] NOT NULL CONSTRAINT [DF_ContentPage_PageType] DEFAULT ((1)),
[CreatedBy] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[CreatedOn] [datetime] NULL,
[ModifiedBy] [nvarchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[ModifiedOn] [datetime] NULL,
[PageViews] [int] NOT NULL CONSTRAINT [DF_ContentPage_PageViews] DEFAULT ((0)),
[Emailed] [int] NOT NULL CONSTRAINT [DF_ContentPage_Emailed] DEFAULT ((0)),
[Emailable] [bit] NOT NULL CONSTRAINT [DF_ContentPage_Emailable] DEFAULT ((1)),
[Printable] [bit] NOT NULL CONSTRAINT [DF_ContentPage_Printable] DEFAULT ((1)),
[ContactButton] [bit] NOT NULL CONSTRAINT [DF_ContentPage_PDFable] DEFAULT ((0)),
[PageHeadingId] [int] NULL CONSTRAINT [DF_ContentPage_PadeHeadingId] DEFAULT ((0)),
[AlternativeTitle] [nvarchar](150) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[RighthandImage] [nvarchar](250) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[IsMicrosite] [bit] NOT NULL CONSTRAINT [DF_ContentPage_IsMicrosite] DEFAULT ((0)),
CONSTRAINT [PK_ContentPage] PRIMARY KEY CLUSTERED
(
[PageId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]