Linq to sql 简单性能差异指引 2 (转)

 测试环境：
        cpu: tk55
        ram: 2g
        hd:120g
        os:vista+sp1
        sql:sql2005开发版
      以下测试只跑一两次，取最后一次（一般第一次会很慢）。

      1.禁用ObjectTrackingEnabled
         当只是查询数据而不跟踪对象状态时禁用，将极大的提供查询性能。性能差异在36倍左右。测试代码：

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            adventureWorks1.ObjectTrackingEnabled = true;
            var q1 = (from p in adventureWorks1.Products select p).ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            adventureWorks2.ObjectTrackingEnabled = false;
            var q2 = (from p in adventureWorks2.Products select p).ToList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

        输出：
        11232000
        312000

     2.不记录输出
        输入记录一般只用在开发阶段，在部署环境中一般不使用。性能差异在17-18倍左右。测试代码：

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            adventureWorks1.Log = Console.Out;
            var q1 = (from p in adventureWorks1.Products select p).ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            var q2 = (from p in adventureWorks2.Products select p).ToList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

输出
SELECT [t0].[ProductID], [t0].[Name], [t0].[ProductNumber], [t0].[MakeFlag], [t0
].[FinishedGoodsFlag], [t0].[Color], [t0].[SafetyStockLevel], [t0].[ReorderPoint
], [t0].[StandardCost], [t0].[ListPrice], [t0].[Size], [t0].[SizeUnitMeasureCode
], [t0].[WeightUnitMeasureCode], [t0].[Weight], [t0].[DaysToManufacture], [t0].[
ProductLine], [t0].[Class], [t0].[Style], [t0].[ProductSubcategoryID], [t0].[Pro
ductModelID], [t0].[SellStartDate], [t0].[SellEndDate], [t0].[DiscontinuedDate],
 [t0].[rowguid], [t0].[ModifiedDate]
FROM [Production].[Product] AS [t0]
-- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.21022.8

       11076000
       624000

      3.编译lambda表达式
         性能差异14-15倍。测试代码：

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            var q1 = (from p in adventureWorks1.Products select p).ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            var compiledQuery = CompiledQuery.Compile((AdventureWorksDataContext ctx) => from p in ctx.Products select p);
            var q2 = compiledQuery(adventureWorks2).ToList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

         输出：
         11076000
         780000

       4.使用DataLoadOptions.LoadWith
            性能差异5-6倍左右。测试代码：

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            var q1 = (from o in adventureWorks1.WorkOrders where o.ProductID == 3 select o).ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            DataLoadOptions options = new DataLoadOptions();
            options.LoadWith<WorkOrder>(o => o.Product);
            adventureWorks2.LoadOptions = options;
            var q2 = (from o in adventureWorks2.WorkOrders where o.ProductID == 3 select o).ToList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

          输出：
          11700000
          2184000

        5.使用延迟加载(系统默认)
           性能差异42-43倍左右。测试代码          

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            adventureWorks1.DeferredLoadingEnabled = true;
            var q1 = (from o in adventureWorks1.WorkOrders where o.ProductID == 3 select o).ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            adventureWorks2.DeferredLoadingEnabled = false;
            var q2 = (from o in adventureWorks1.WorkOrders where o.ProductID == 3 select o).ToList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

           输出：
          26676000
          624000 

        6.使用sql语句
            性能差异 7倍左右

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            var q1 = (from o in adventureWorks1.WorkOrders where o.ProductID == 3 select o).ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            var q2 = adventureWorks2.ExecuteQuery<Product>(@"SELECT [t0].[WorkOrderID], [t0].[ProductID], [t0].[OrderQty], [t0].[StockedQty], [t0].[ScrappedQty], [t0].[StartDate], [t0].[EndDate], [t0].[DueDate], [t0].[ScrapReasonID], [t0].[ModifiedDate]
                                                            FROM [Production].[WorkOrder] AS [t0]
                                                            WHERE [t0].[ProductID] = 3").ToList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

            输出：
            11856000
            1716000

        7.使用储存过程
            性能差异20倍左右。测试代码：

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            var q1 = (from o in adventureWorks1.WorkOrders where o.ProductID == 3 select o).ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            var q2 = adventureWorks2.GetWorkOrderByProductID(3).ToList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

-- ================================================
-- Template generated from Template Explorer using:
-- Create Procedure (New Menu).SQL
--
-- Use the Specify Values for Template Parameters 
-- command (Ctrl-Shift-M) to fill in the parameter 
-- values below.
--
-- This block of comments will not be included in
-- the definition of the procedure.
-- ================================================
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:        <Author,,Name>
-- Create date: <Create Date,,>
-- Description:    <Description,,>
-- =============================================
CREATE PROCEDURE Production.GetWorkOrderByProductID
    -- Add the parameters for the stored procedure here
    @ProductID int
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    SELECT [t0].[WorkOrderID], [t0].[ProductID], [t0].[OrderQty], [t0].[StockedQty], [t0].[ScrappedQty], [t0].[StartDate], [t0].[EndDate], [t0].[DueDate], [t0].[ScrapReasonID], [t0].[ModifiedDate]
                                                            FROM [Production].[WorkOrder] AS [t0]
                                                            WHERE [t0].[ProductID] = @ProductID
END
GO

            输出：
            12168000
            624000 

    8、获取数据以用于数据绑定  
        性能差异1.5倍左右。测试代码：  

            AdventureWorksDataContext adventureWorks1 = new AdventureWorksDataContext();
            DateTime d1 = DateTime.Now;
            var q1 = adventureWorks1.Products.ToList();
            DateTime d2 = DateTime.Now;
            Console.WriteLine(d2.Ticks - d1.Ticks);

            AdventureWorksDataContext adventureWorks2 = new AdventureWorksDataContext();
            DateTime d3 = DateTime.Now;
            var q2 = adventureWorks2.WorkOrders.GetNewBindingList();
            DateTime d4 = DateTime.Now;
            Console.WriteLine(d4.Ticks - d3.Ticks);

        输出：
        10140000
        6708000