Hello, we have a query that executes very differently in different environments.Here are the stats:Development: 2 secQA: 7 secProduction: around 1 min (off the pick hours)The longer execution times cause timeout and make the page of little use on Production. We have checked the execution plan, and optimization through indexing, no further improvements - it seems. And yet there must be a reason for a 1 min discrepancy. Actually, it may be that we miss something while comparing execution plans' among the servers. Where could we look for resolving this. All three servers use same SQL Server version and the prod machine seems to perform consistently on other queries/SP. Below is the query. We would also appreciate if someone could take a look at the execution plans, may be a clue could be found there. Thank you.SELECT TOP (20)[Project10].[C1] AS [C1],[Project10].[ReviewID] AS [ReviewID],[Project10].[BusinessID] AS [BusinessID], [Project10].[Name] AS [Name], [Project10].[Description] AS [Description], [Project10].[Rating] AS [Rating], [Project10].[C4] AS [C2], [Project10].[Reviewer] AS [Reviewer], [Project10].[City] AS [City], [Project10].[CreateDate] AS [CreateDate], [Project10].[UpdateDate] AS [UpdateDate], [Project10].[Name1] AS [Name1], [Project10].[C2] AS [C3], [Project10].[C3] AS [C4] FROM ( SELECT [Project10].[ReviewID] AS [ReviewID], [Project10].[Description] AS [Description], [Project10].[Rating] AS [Rating], [Project10].[Reviewer] AS [Reviewer], [Project10].[City] AS [City], [Project10].[CreateDate] AS [CreateDate], [Project10].[UpdateDate] AS [UpdateDate], [Project10].[BusinessID] AS [BusinessID], [Project10].[Name] AS [Name], [Project10].[Name1] AS [Name1], [Project10].[C1] AS [C1], [Project10].[C2] AS [C2], [Project10].[C3] AS [C3], [Project10].[C4] AS [C4], row_number() OVER (ORDER BY [Project10].[BusinessID] ASC) AS [row_number] FROM ( SELECT [Project9].[ReviewID] AS [ReviewID], [Project9].[Description] AS [Description], [Project9].[Rating] AS [Rating], [Project9].[Reviewer] AS [Reviewer], [Project9].[City] AS [City], [Project9].[CreateDate] AS [CreateDate], [Project9].[UpdateDate] AS [UpdateDate], [Extent17].[BusinessID] AS [BusinessID], [Extent18].[Name] AS [Name], [Extent19].[Name] AS [Name1], 1 AS [C1], [Project9].[C1] AS [C2], [Project9].[C2] AS [C3], [Project9].[C3] AS [C4] FROM (SELECT [Project5].[ReviewID] AS [ReviewID], [Project5].[Description] AS [Description], [Project5].[Rating] AS [Rating], [Project5].[Reviewer] AS [Reviewer], [Project5].[City] AS [City], [Project5].[CreateDate] AS [CreateDate], [Project5].[UpdateDate] AS [UpdateDate], [Project5].[BusinessID] AS [BusinessID], [Project5].[IsMain] AS [IsMain], [Project5].[TypeID] AS [TypeID], [Project5].[C1] AS [C1], [Project5].[C2] AS [C2], (SELECT TOP (1) [Extent10].[DisplayValue] AS [DisplayValue] FROM [gb_business].[BusinessContacts] AS [Extent9] LEFT OUTER JOIN [gb_business].[PersonalCommunication] AS [Extent10] ON EXISTS (SELECT cast(1 as bit) AS [C1] FROM ( SELECT cast(1 as bit) AS X ) AS [SingleRowTable2] LEFT OUTER JOIN (SELECT [Extent11].[PersonID] AS [PersonID] FROM [gb_business].[Person] AS [Extent11] WHERE [Extent9].[PersonID] = [Extent11].[PersonID] ) AS [Project6] ON 1 = 1 INNER JOIN [gb_business].[Person] AS [Extent12] ON [Project6].[PersonID] = [Extent12].[PersonID] WHERE [Extent10].[PersonID] = [Extent12].[PersonID] ) LEFT OUTER JOIN [gb_business].[ContactType] AS [Extent13] ON [Extent9].[ContactTypeID] = [Extent13].[ContactTypeID] LEFT OUTER JOIN [gb_business].[CommunicationType] AS [Extent14] ON [Extent10].[CommunicationTypeID] = [Extent14].[CommunicationTypeID] LEFT OUTER JOIN [gb_business].[Business] AS [Extent15] ON [Extent9].[BusinessID] = [Extent15].[BusinessID] INNER JOIN [gb_business].[Business] AS [Extent16] ON [Extent15].[BusinessID] = [Extent16].[BusinessID] WHERE ([Extent13].[ContactTypeID] = 1) AND ([Extent14].[CommunicationTypeID] = 4) AND ([Project5].[BusinessID] = [Extent16].[BusinessID])) AS [C3] FROM ( SELECT [Project4].[ReviewID] AS [ReviewID], [Project4].[Description] AS [Description], [Project4].[Rating] AS [Rating], [Project4].[Reviewer] AS [Reviewer], [Project4].[City] AS [City], [Project4].[CreateDate] AS [CreateDate], [Project4].[UpdateDate] AS [UpdateDate], [Project4].[BusinessID] AS [BusinessID], [Project4].[IsMain] AS [IsMain], [Project4].[TypeID] AS [TypeID], [Project4].[C1] AS [C1], (SELECT COUNT([Extent7].[ReviewHistoryID]) AS [A1] FROM [gb_business].[ReviewHistory] AS [Extent7] LEFT OUTER JOIN [gb_business].[ReviewStatus] AS [Extent8] ON [Extent7].[ReviewStatusID] = [Extent8].[ReviewStatusID] WHERE ([Project4].[ReviewID] = [Extent7].[ReviewID]) AND ([Extent8].[ReviewStatusID] = 1)) AS [C2] FROM ( SELECT [Extent1].[ReviewID] AS [ReviewID], [Extent1].[Description] AS [Description], [Extent1].[Rating] AS [Rating], [Extent1].[Reviewer] AS [Reviewer], [Extent1].[City] AS [City], [Extent1].[CreateDate] AS [CreateDate], [Extent1].[UpdateDate] AS [UpdateDate], [Extent1].[BusinessID] AS [BusinessID], [Extent2].[IsMain] AS [IsMain], [Extent2].[TypeID] AS [TypeID], (SELECT TOP (1) [Project3].[StatusDate] AS [StatusDate] FROM ( SELECT [Extent5].[StatusDate] AS [StatusDate] FROM [gb_business].[ReviewHistory] AS [Extent5] LEFT OUTER JOIN [gb_business].[ReviewStatus] AS [Extent6] ON [Extent5].[ReviewStatusID] = [Extent6].[ReviewStatusID] WHERE ([Extent1].[ReviewID] = [Extent5].[ReviewID]) AND ([Extent6].[ReviewStatusID] = 1) ) AS [Project3] ORDER BY [Project3].[StatusDate] DESC) AS [C1] FROM [gb_business].[Review] AS [Extent1] LEFT OUTER JOIN [gb_listing].[RegionalService] AS [Extent2] ON EXISTS (SELECT cast(1 as bit) AS [C1] FROM ( SELECT cast(1 as bit) AS X ) AS [SingleRowTable1] LEFT OUTER JOIN (SELECT [Extent3].[BusinessID] AS [BusinessID] FROM [gb_business].[Business] AS [Extent3] WHERE [Extent1].[BusinessID] = [Extent3].[BusinessID] ) AS [Project1] ON 1 = 1 INNER JOIN [gb_business].[Business] AS [Extent4] ON [Project1].[BusinessID] = [Extent4].[BusinessID] WHERE [Extent2].[BusinessID] = [Extent4].[BusinessID] ) ) AS [Project4] ) AS [Project5] ) AS [Project9] LEFT OUTER JOIN [gb_business].[Business] AS [Extent17] ON [Project9].[BusinessID] = [Extent17].[BusinessID] LEFT OUTER JOIN [gb_business].[Business] AS [Extent18] ON [Project9].[BusinessID] = [Extent18].[BusinessID] LEFT OUTER JOIN [gb_listing].[RegionalServiceType] AS [Extent19] ON [Project9].[TypeID] = [Extent19].[RegionalServiceTypeID] WHERE [Project9].[IsMain] = 1 ) AS [Project10]) AS [Project10]WHERE [Project10].[row_number] > 0ORDER BY [Project10].[BusinessID] ASC