Question

我有一个SQL Server查询在使用offset / fetch通过分页检索数据时表现不佳。较早的页面返回结果非常快，但后来的页面非常慢并且在我们的系统中造成了瓶颈。它正在加入两个临时表（#A和#T）。这是查询的简化版本：

    Select
        I.CustomerID,
        I.InvoiceID,
        I.ItemID,
        TI1.TrackID as TrackID1,
        TI1.ItemName as ItemName1,
        TI1.TrackCatID as TrackCatID1,
        TI1.CategoryName as CategoryName1,
        TI2.TrackID as TrackID2,
        TI2.ItemName as ItemName2,
        TI2.TrackCatID as TrackCatID2,
        TI2.CategoryName as CategoryName2,
        A.AccID,
        A.Name as AccountName,
        A.utimestamp as UpdateTimeStamp
    FROM 
        #A A
            Inner Join [dbo].[Item] I WITH(FORCESEEK)
                On 
                A.CustomerID = I.CustomerID And
                A.AccountID = I.AccountID
            Left Join #T TI1 On
                I.CustomerID = TI1.CustomerID And
                I.TrackID1 = TI1.TrackID
            Left Join #T TI2 On
                I.CustomerID = TI2.CustomerID And
                I.TrackID2 = TI2.TrackID
    Order by
        A.utimestamp
    Offset 0 Rows Fetch Next 1000 Rows Only

临时表定义为：

Create table #T (CustomerID uniqueidentifier, TrackCatID uniqueidentifier, TrackID uniqueidentifier, ItemName varchar(100), CategoryName varchar(100),PRIMARY KEY (CustomerID,TrackID))

Create table #A (CustomerID uniqueidentifier, AccountID uniqueidentifier, Name varchar(100), utimestamp timestamp, PRIMARY KEY (CustomerID, AccountID))

关于DB表[dbo]。[Item]，它被定义为：

CREATE TABLE [dbo].[Item](
        [Sequence] [int] IDENTITY(1,1) NOT NULL,
        [CustomerID] [uniqueidentifier] NOT NULL,
        [ItemID] [uniqueidentifier] NOT NULL,
        [AccountID] [uniqueidentifier] NULL,
        [TrackID1] [uniqueidentifier] NULL,
        [TrackID2] [uniqueidentifier] NULL,
 CONSTRAINT [PK_Item] PRIMARY KEY NONCLUSTERED 
(
    [CustomerID] ASC,
    [ItemID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 80) ON [PRIMARY],
 CONSTRAINT [CX_Item] UNIQUE CLUSTERED 
(
    [CustomerID] ASC,
    [Sequence] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 80) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO

并且有许多索引，每个索引都有几列：

项目索引

1: CusotmerID, Sequence 
2: CusotmerID, AccountId, Sequence 
3: CusotmerID, TrackId1 
4: CusotmerID, TrackId2 
5: CusotmerID, ItemID

我是否遗漏了导致后续分页查询变慢的问题？注意：“偏移0行”中的0对于每页增加1000。另外，我在临时表#A中添加了一个索引，并没有看到结果的改进： CREATE INDEX IDX_Timestamp ON #A（utimestamp）

偏移/获取查询缓慢

0 个答案: