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テーブル エイリアスを使用すると SQL ビューの選択が非常に遅くなる (25 秒) のに、エイリアスを削除すると (2 秒) 高速に実行される理由に困惑しています。

-このクエリには 25 秒かかります。

SELECT [Extent1].[Id]                        AS [Id],
       [Extent1].[ProjectId]                 AS [ProjectId],
       [Extent1].[ProjectWorkOrderId]        AS [ProjectWorkOrderId],
       [Extent1].[Project]                   AS [Project],
       [Extent1].[SubcontractorId]           AS [SubcontractorId],
       [Extent1].[Subcontractor]             AS [Subcontractor],
       [Extent1].[ValuationNumber]           AS [ValuationNumber],
       [Extent1].[WorksOrderName]            AS [WorksOrderName],
       [Extent1].[NewGross],
       [Extent1].[CumulativeGross],
       [Extent1].[CreateByName]              AS [CreateByName],
       [Extent1].[CreateDate]                AS [CreateDate],
       [Extent1].[FinalDateForPayment]       AS [FinalDateForPayment],
       [Extent1].[CreateByEmail]             AS [CreateByEmail],
       [Extent1].[Deleted]                   AS [Deleted],
       [Extent1].[ValuationStatusCategoryId] AS [ValuationStatusCategoryId]
FROM   [dbo].[ValuationsTotal] AS [Extent1]

-このクエリには 2 秒かかります。

SELECT [Id],
       [ProjectId],
       [Project],
       [SubcontractorId],
       [Subcontractor],
       [NewGross],
       [ProjectWorkOrderId],
       [ValuationNumber],
       [WorksOrderName],
       [CreateByName],
       [CreateDate],
       [CreateByEmail],
       [Deleted],
       [ValuationStatusCategoryId],
       [FinalDateForPayment],
       [CumulativeGross]
FROM   [dbo].[ValuationsTotal]

これは私のSQLビューコードです -

WITH ValuationTotalsTemp(Id, ProjectId, Project, SubcontractorId, Subcontractor, WorksOrderName, NewGross, ProjectWorkOrderId, ValuationNumber, CreateByName, CreateDate, CreateByEmail, Deleted, ValuationStatusCategoryId, FinalDateForPayment)
     AS (SELECT vi.ValuationId                             AS Id,
                v.ProjectId,
                p.NAME,
                b.Id                                       AS Expr1,
                b.NAME                                     AS Expr2,
                wo.OrderNumber,
                SUM(vi.ValuationQuantity * pbc.BudgetRate) AS 'NewGross',
                sa.ProjectWorkOrderId,
                v.ValuationNumber,
                up.FirstName + ' ' + up.LastName           AS Expr3,
                v.CreateDate,
                up.Email,
                v.Deleted,
                v.ValuationStatusCategoryId,
                sa.FinalDateForPayment
         FROM   dbo.ValuationItems AS vi
                INNER JOIN dbo.ProjectBudgetCosts AS pbc
                        ON vi.ProjectBudgetCostId = pbc.Id
                INNER JOIN dbo.Valuations AS v
                        ON vi.ValuationId = v.Id
                INNER JOIN dbo.ProjectSubcontractorApplications AS sa
                        ON sa.Id = v.ProjectSubcontractorApplicationId
                INNER JOIN dbo.Projects AS p
                        ON p.Id = v.ProjectId
                INNER JOIN dbo.ProjectWorkOrders AS wo
                        ON wo.Id = sa.ProjectWorkOrderId
                INNER JOIN dbo.ProjectSubcontractors AS sub
                        ON sub.Id = wo.ProjectSubcontractorId
                INNER JOIN dbo.Businesses AS b
                        ON b.Id = sub.BusinessId
                INNER JOIN dbo.UserProfile AS up
                        ON up.Id = v.CreateBy
         WHERE ( vi.Deleted = 0 )
               AND ( v.Deleted = 0 )
         GROUP  BY vi.ValuationId,
                   v.ProjectId,
                   p.NAME,
                   b.Id,
                   b.NAME,
                   wo.OrderNumber,
                   sa.ProjectWorkOrderId,
                   v.ValuationNumber,
                   up.FirstName + ' ' + up.LastName,
                   v.CreateDate,
                   up.Email,
                   v.Deleted,
                   v.ValuationStatusCategoryId,
                   sa.FinalDateForPayment)
SELECT Id,
       ProjectId,
       Project,
       SubcontractorId,
       Subcontractor,
       NewGross,
       ProjectWorkOrderId,
       ValuationNumber,
       WorksOrderName,
       CreateByName,
       CreateDate,
       CreateByEmail,
       Deleted,
       ValuationStatusCategoryId,
       FinalDateForPayment,
       (SELECT SUM(NewGross) AS Expr1
        FROM   ValuationTotalsTemp AS tt
        WHERE ( ProjectWorkOrderId = t.ProjectWorkOrderId )
              AND ( t.ValuationNumber >= ValuationNumber )
        GROUP  BY ProjectWorkOrderId) AS CumulativeGross
FROM   ValuationTotalsTemp AS t

これはなぜですか？

これはEntity Frameworkから生成されるため、SQLクエリはテーブルエイリアスで実行されるため、これを変更する方法はありません。パフォーマンスに影響を与えずにテーブル エイリアスを処理できるように、SQL ビューを変更する必要があります。

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3 に答える 3

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2 つのクエリは異なります (列の順序!)。最初のクエリがインデックスを使用しているため、はるかに高速であると想定するのが妥当です。エイリアシングと関係があるとは思えません。

于 2015-12-08T18:37:36.970 に答える