我在DB各地90K的记录,我运行此查询:查询与ROW_NUMBER()花费过多时间
它需要太多的时间(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
然而,这第二查询执行1秒:
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)你能否建议为什么我的第一个查询需要这么长时间来执行?我想优化我的第一个查询,因为它是由一个自动化程序生成的(它的源代码有,但我不能移动Select中的RowNumber)。
2)执行此操作的时间也取决于peta_rn。如果我给peta_rn> 50000和peta_rn < = 50100,则需要执行无望的时间。你能否也请建议为什么要执行的时间取决于我试图读取的行,因为最终我只试图一次读取100行。
你有没有索引peta_rn?它会提高你的查询性能。 – Habibillah
@habibillah:我应该如何索引peta_rn?它只是一个计算字段,它是* ROW_NUMBER()OVER(按d.DocumentID desc排序)* – Jack