我有一个使用Linq2SQL“尖刺”的项目,现在正在运行一些主要的查询性能问题。去搞清楚。SQLServer查询优化问题
Linq实际上在简单的查询和命令场景下工作得很好,但有一些过滤器激烈的查询需要重写为Sprocs。
我想知道是否有人可以给我一些高级指针,以节省优化由Linq生成的怪物查询的时间。
我认为用临时表替换所有的“连接(@ p1,@ p2)”内部连接的子句将是一个好的开始。
所有外键和where子句列都被编入索引。
任何见解都值得赞赏。
下面的代码:
SELECT [t9].[ID], [t9].[Description], [t9].[AreaCodeID], [t9].[BedroomCodeID], [t9].[BathroomCodeID], [t9].[DwellingCodeID], [t9].[LandlordID], [t9].[ParsedItemID], [t9].[DeletedReasonID], [t9].[CoordinateID], [t9].[Address], [t9].[PhonePrefix1], [t9].[Phone1], [t9].[PhonePrefix2], [t9].[Phone2], [t9].[EmailAddress], [t9].[RentAmount], [t9].[SquareFeet], [t9].[DateAvailable], [t9].[DateCreated], [t9].[IsDeleted], [t9].[RowVersion], [t9].[ID2], [t9].[ParentAreaCodeID], [t9].[AreaGroupID], [t9].[Description2], [t9].[Order], [t9].[IsTopLevelArea], [t9].[IsDeleted2], [t9].[ID3], [t9].[CityID], [t9].[Description3], [t9].[Order2], [t9].[IsPrimary], [t9].[IsDeleted3], [t9].[ID4], [t9].[HostURL], [t9].[Description4], [t9].[Rate], [t9].[RateTax], [t9].[RateTaxCode], [t9].[Currency], [t9].[LogoImageFileName], [t9].[FlashQuotesFileName], [t9].[TestimonialQuotesFileName], [t9].[GoogleAnalyticsTrackingCode], [t9].[GoogleMapsAPIKey], [t9].[IDHash], [t9].[test], [t9].[ID5], [t9].[Description5], [t9].[ID6], [t9].[Description6], [t9].[Order3], [t9].[IsDeleted4], [t9].[ID7], [t9].[Description7], [t9].[IsDeleted5], [t9].[Order4]
FROM (
SELECT TOP (100) [t0].[ID], [t0].[Description], [t0].[AreaCodeID], [t0].[BedroomCodeID], [t0].[BathroomCodeID], [t0].[DwellingCodeID], [t0].[LandlordID], [t0].[ParsedItemID], [t0].[DeletedReasonID], [t0].[CoordinateID], [t0].[Address], [t0].[PhonePrefix1], [t0].[Phone1], [t0].[PhonePrefix2], [t0].[Phone2], [t0].[EmailAddress], [t0].[RentAmount], [t0].[SquareFeet], [t0].[DateAvailable], [t0].[DateCreated], [t0].[IsDeleted], [t0].[RowVersion], [t1].[ID] AS [ID2], [t1].[ParentAreaCodeID], [t1].[AreaGroupID], [t1].[Description] AS [Description2], [t1].[Order], [t1].[IsTopLevelArea], [t1].[IsDeleted] AS [IsDeleted2], [t2].[ID] AS [ID3], [t2].[CityID], [t2].[Description] AS [Description3], [t2].[Order] AS [Order2], [t2].[IsPrimary], [t2].[IsDeleted] AS [IsDeleted3], [t3].[ID] AS [ID4], [t3].[HostURL], [t3].[Description] AS [Description4], [t3].[Rate], [t3].[RateTax], [t3].[RateTaxCode], [t3].[Currency], [t3].[LogoImageFileName], [t3].[FlashQuotesFileName], [t3].[TestimonialQuotesFileName], [t3].[GoogleAnalyticsTrackingCode], [t3].[GoogleMapsAPIKey], [t3].[IDHash], [t5].[test], [t5].[ID] AS [ID5], [t5].[Description] AS [Description5], [t6].[ID] AS [ID6], [t6].[Description] AS [Description6], [t6].[Order] AS [Order3], [t6].[IsDeleted] AS [IsDeleted4], [t7].[ID] AS [ID7], [t7].[Description] AS [Description7], [t7].[IsDeleted] AS [IsDeleted5], [t7].[Order] AS [Order4]
FROM [dbo].[Listing] AS [t0]
INNER JOIN ([dbo].[AreaCode] AS [t1]
INNER JOIN ([dbo].[AreaGroup] AS [t2]
INNER JOIN [dbo].[City] AS [t3] ON [t3].[ID] = [t2].[CityID]) ON [t2].[ID] = [t1].[AreaGroupID]) ON [t1].[ID] = [t0].[AreaCodeID]
LEFT OUTER JOIN (
SELECT 1 AS [test], [t4].[ID], [t4].[Description]
FROM [dbo].[BathroomCode] AS [t4]
) AS [t5] ON [t5].[ID] = [t0].[BathroomCodeID]
INNER JOIN [dbo].[BedroomCode] AS [t6] ON [t6].[ID] = [t0].[BedroomCodeID]
INNER JOIN [dbo].[DwellingCode] AS [t7] ON [t7].[ID] = [t0].[DwellingCodeID]
WHERE (NOT ([t0].[IsDeleted] = 1)) AND (EXISTS(
SELECT NULL AS [EMPTY]
FROM [dbo].[ListingMiscellaneousCode] AS [t8]
WHERE ([t8].[MiscellaneousCodeID] IN (@p0, @p1, @p2, @p3, @p4, @p5, @p6)) AND ([t8].[ListingID] = [t0].[ID])
)) AND ([t0].[DwellingCodeID] IN (@p7)) AND ([t0].[AreaCodeID] IN (@p8, @p9, @p10, @p11, @p12, @p13, @p14, @p15, @p16, @p17, @p18, @p19, @p20, @p21, @p22, @p23, @p24, @p25, @p26, @p27, @p28, @p29, @p30, @p31, @p32, @p33, @p34, @p35, @p36, @p37, @p38, @p39, @p40, @p41, @p42, @p43, @p44, @p45, @p46, @p47, @p48, @p49, @p50, @p51, @p52, @p53, @p54, @p55, @p56, @p57, @p58, @p59, @p60, @p61, @p62, @p63, @p64, @p65, @p66, @p67, @p68, @p69, @p70, @p71, @p72, @p73, @p74, @p75, @p76, @p77, @p78, @p79, @p80, @p81, @p82, @p83, @p84, @p85, @p86, @p87, @p88, @p89, @p90, @p91, @p92, @p93, @p94, @p95, @p96, @p97, @p98, @p99, @p100, @p101, @p102, @p103, @p104, @p105, @p106, @p107, @p108, @p109, @p110, @p111))
) AS [t9]
ORDER BY [t9].[DateCreated] DESC, [t9].[RentAmount], [t9].[Description2]
正如你可能已经猜到,这个问题部分完全位于where子句。删除这会导致查询进行得非常快。即使有了这个Where子句,它并不是很慢(大约1秒),但问题是,我还必须根据类似的样式查询返回当前数据的各种计数。整个过程由于具有较差的Where子句的多个查询而花费超过5秒。
我不明白的另一件事是,改变查询的页面大小,即“...选择TOP(100)...”到更高的数字,如“... Select TOP(5000) ...“不会减慢查询的速度。这对我来说很奇怪,更多的证据表明,我认为这个问题有望通过修改后的sql来解决。
您还会注意到,Where子句特别是(对于areacodeid)查询了近100个参数。这是设计。现在我可以在父表中进行破解,以减少一些反规范化的代价,但我希望首先有一个纯SQL修复,它可以让我有效地加入到临时表中,其中包含100个参数。
感谢您的帮助。
如果您包含底层架构(它们上的表和索引)以及原始Linq查询(或多个查询),我相信它可以修复。看起来不像有什么不寻常的东西,如果它有性能问题,它可以修复而不诉诸于存储的特效。 – KristoferA 2009-10-27 03:13:04
......哦,忘了补充......如果查询性能不够好,先查找性能问题的原因。然后优化。盲目优化只是浪费时间。如果您可以包含[链接]执行计划和查询的I/O统计信息,那也同样有帮助。 – KristoferA 2009-10-27 03:19:28