用row_number（）查询花费太多时间

Question

我的数据库中大约有9万条记录，并且运行以下查询：

这需要太多时间（大约4秒）：

SELECT * FROM (SELECT 
    ROW_NUMBER() OVER (Order By DocumentID desc) peta_rn, peta_query.* From 
    (
            Select   d.DocumentID, d.IsReEfiled, d.IGroupID, d.ITypeID, d.RecordingDateTime, dbo.GetLatestStatusDateTime(d.DocumentID) as LatestStatusDatetime, 
                    dbo.FnCanChangeDocumentStatus(d.DocumentStatusID,d.DocumentID) as CanChangeStatus, d.IDate, d.InstrumentID, d.DocumentStatusID,ig.Abbreviation as IGroupAbbreviation, 
                    u.Username, j.JDAbbreviation, inf.DocumentName,
                    it.Abbreviation as ITypeAbbreviation, d.DocumentDate, ds.Abbreviation as DocumentStatusAbbreviation,
                    dbo.GetFlatDocumentName(d.DocumentID) as FlatDocumentName 
                    From Documents d Inner Join IGroupes ig On d.IGroupID = ig.IGroupID 
                            Left Join ITypes it On d.ITypeID = it.ITypeID 
                            Left Join Users u On u.UserID = d.UserID 
                            Left Join DocumentStatuses ds On d.DocumentStatusID = ds.DocumentStatusID 
                            Left Join InstrumentFiles inf On d.DocumentID = inf.DocumentID 
                            Inner Join Jurisdictions j on j.JurisdictionID = d.JurisdictionID                           
    ) as peta_query) peta_paged WHERE peta_rn>12000 AND peta_rn<=12100

但是，此第二个查询将在1秒内执行：

SELECT * FROM (SELECT 
    peta_query.* From 
    (
            Select  ROW_NUMBER() OVER (Order By d.DocumentID desc) peta_rn, d.DocumentID, d.IsReEfiled, d.IGroupID, d.ITypeID, d.RecordingDateTime, dbo.GetLatestStatusDateTime(d.DocumentID) as LatestStatusDatetime, 
                    dbo.FnCanChangeDocumentStatus(d.DocumentStatusID,d.DocumentID) as CanChangeStatus, d.IDate, d.InstrumentID, d.DocumentStatusID,ig.Abbreviation as IGroupAbbreviation, 
                    u.Username, j.JDAbbreviation, inf.DocumentName,
                    it.Abbreviation as ITypeAbbreviation, d.DocumentDate, ds.Abbreviation as DocumentStatusAbbreviation,
                    dbo.GetFlatDocumentName(d.DocumentID) as FlatDocumentName 
                    From Documents d Inner Join IGroupes ig On d.IGroupID = ig.IGroupID 
                            Left Join ITypes it On d.ITypeID = it.ITypeID 
                            Left Join Users u On u.UserID = d.UserID 
                            Left Join DocumentStatuses ds On d.DocumentStatusID = ds.DocumentStatusID 
                            Left Join InstrumentFiles inf On d.DocumentID = inf.DocumentID 
                            Inner Join Jurisdictions j on j.JurisdictionID = d.JurisdictionID                           
    ) as peta_query) peta_paged WHERE peta_rn>12000 AND peta_rn<=12100

我的问题是：

1）您能否建议为什么我的第一个查询要花这么长时间执行？ 我想优化我的第一个查询，因为它是由一个自动程序生成的（我有它的源，但是我不能在Select内移动RowNumber）。

2）执行此操作的时间还取决于peta_rn。 如果我给peta_rn> 50000并且peta_rn <= 50100，则执行该程序将花费无望的时间。 您能否也提出一个建议，为什么执行时间取决于我要获取的行，因为最终我一次只能获取100行。

Answer 1

只是为了好玩-您可以尝试此CTE并查看其性能吗？ 我不完全理解为什么您在那里有三个嵌套子查询。

;WITH PetaQuery AS
(
    SELECT 
        ROW_NUMBER() OVER (ORDER BY d.DocumentID DESC) peta_rn, 
        d.DocumentID, d.IsReEfiled, d.IGroupID, d.ITypeID, d.RecordingDateTime, 
        dbo.GetLatestStatusDateTime(d.DocumentID) as LatestStatusDatetime, 
        dbo.FnCanChangeDocumentStatus(d.DocumentStatusID,d.DocumentID) as CanChangeStatus, 
        d.IDate, d.InstrumentID, d.DocumentStatusID,ig.Abbreviation as IGroupAbbreviation, 
        u.Username, j.JDAbbreviation, inf.DocumentName,
        it.Abbreviation as ITypeAbbreviation, d.DocumentDate, ds.Abbreviation as DocumentStatusAbbreviation,
        dbo.GetFlatDocumentName(d.DocumentID) as FlatDocumentName 
    FROM 
        Documents d 
    INNER JOIN 
        IGroupes ig On d.IGroupID = ig.IGroupID 
    LEFT OUTER JOIN 
        ITypes it On d.ITypeID = it.ITypeID 
    LEFT OUTER JOIN 
        Users u On u.UserID = d.UserID 
    LEFT OUTER JOIN 
        DocumentStatuses ds On d.DocumentStatusID = ds.DocumentStatusID 
    LEFT OUTER JOIN 
        InstrumentFiles inf On d.DocumentID = inf.DocumentID 
    INNER JOIN 
        Jurisdictions j on j.JurisdictionID = d.JurisdictionID                           
) 
SELECT * FROM PetaQuery
WHERE peta_rn > 12000 AND peta_rn <= 12100

这与原始查询具有相同的响应时间吗？

如果是这样，请检查：

• 您在所有外键（ IGroupID ， ITypeID ， UserID ， DocumentStatusID ， DocumentID ， JurisdictionID ）上都有索引吗？ 这对于提高JOIN性能至关重要