converting sql statement back to lambda expression - entity-framework

Question

I have the query below, and its sql code. It's running really slow, so it was re written in sql, now I'm just not sure how to convert the sql back to a lambda expression.
This is the part of the expression giving me the problems, somewhere in
r.RecordProducts.Any()
records = records
.Include(r => r.Employer)
.Include(r => r.Contractor)
.Include(r => r.RecordProducts)
.ThenInclude(rp => rp.ProductDefendant.Defendant)
.Where(r => EF.Functions.Like(r.Employer.DefendantCode, "%" + input.DefendantCode + "%")
|| EF.Functions.Like(r.Contractor.DefendantCode, "%" + input.DefendantCode + "%")
|| r.RecordProducts.Any(rp => EF.Functions.Like(rp.ProductDefendant.Defendant.DefendantCode, "%" + input.DefendantCode + "%") && rp.IsActive == true));
the any clause does an exist and some funky stuff in the sql where clause below
SELECT [t].[Id], [t].[StartDate], [t].[EndDate], [t].[WitnessName], [t].[SourceCode], [t].[JobsiteName], [t].[ShipName], [t].[EmployerCode]
FROM (
SELECT DISTINCT [r].[RecordID] AS [Id], [r].[StartDate], [r].[EndDate], [r.Witness].[FullName] AS [WitnessName], CASE
WHEN [r].[SourceID] IS NOT NULL
THEN [r.Source].[SourceCode] ELSE N'zzzzz'
END AS [SourceCode], CASE
WHEN [r].[JobsiteID] IS NOT NULL
THEN [r.Jobsite].[JobsiteName] ELSE N'zzzzz'
END AS [JobsiteName], CASE
WHEN [r].[ShipID] IS NOT NULL
THEN [r.Ship].[ShipName] ELSE N'zzzzz'
END AS [ShipName], CASE
WHEN [r].[EmployerID] IS NOT NULL
THEN [r.Employer].[DefendantCode] ELSE N'zzzzz'
END AS [EmployerCode]
FROM [Records] AS [r]
LEFT JOIN [Ships] AS [r.Ship] ON [r].[ShipID] = [r.Ship].[ShipID]
LEFT JOIN [Jobsites] AS [r.Jobsite] ON [r].[JobsiteID] = [r.Jobsite].[JobsiteID]
LEFT JOIN [Sources] AS [r.Source] ON [r].[SourceID] = [r.Source].[SourceID]
LEFT JOIN [Witnesses] AS [r.Witness] ON [r].[WitnessID] = [r.Witness].[WitnessID]
LEFT JOIN [Defendants] AS [r.Contractor] ON [r].[ContractorID] = [r.Contractor].[DefendantID]
LEFT JOIN [Defendants] AS [r.Employer] ON [r].[EmployerID] = [r.Employer].[DefendantID]
WHERE ([r].[IsActive] = 1) AND (([r.Employer].[DefendantCode] LIKE (N'%' + 'cert') + N'%' OR [r.Contractor].[DefendantCode] LIKE (N'%' + 'cert') + N'%') OR EXISTS (
SELECT 1
FROM [Records_Products] AS [rp]
INNER JOIN [Product_Defendant] AS [rp.ProductDefendant] ON [rp].[DefendantProductID] = [rp.ProductDefendant].[DefendantProductID]
INNER JOIN [Defendants] AS [rp.ProductDefendant.Defendant] ON [rp.ProductDefendant].[DefendantID] = [rp.ProductDefendant.Defendant].[DefendantID]
WHERE ([rp.ProductDefendant.Defendant].[DefendantCode] LIKE (N'%' + 'cert') + N'%' AND ([rp].[IsActive] = 1)) AND ([r].[RecordID] = [rp].[RecordID])))
) AS [t]
ORDER BY [t].[SourceCode]
OFFSET 0 ROWS FETCH NEXT 500 ROWS ONLY
Here is the new sql that works better, just not sure how to convert it back to a lambda expression
SELECT [t].[Id]
,[t].[StartDate]
,[t].[EndDate]
,[t].[WitnessName]
,[t].[SourceCode]
,[t].[JobsiteName]
,[t].[ShipName]
,[t].[EmployerCode]
FROM (
SELECT DISTINCT [r].[RecordID] AS [Id]
,[r].[StartDate]
,[r].[EndDate]
,[r.Witness].[FullName] AS [WitnessName]
,CASE
WHEN [r].[SourceID] IS NOT NULL
THEN [r.Source].[SourceCode]
ELSE N'zzzzz'
END AS [SourceCode]
,CASE
WHEN [r].[JobsiteID] IS NOT NULL
THEN [r.Jobsite].[JobsiteName]
ELSE N'zzzzz'
END AS [JobsiteName]
,CASE
WHEN [r].[ShipID] IS NOT NULL
THEN [r.Ship].[ShipName]
ELSE N'zzzzz'
END AS [ShipName]
,CASE
WHEN [r].[EmployerID] IS NOT NULL
THEN [r.Employer].[DefendantCode]
ELSE N'zzzzz'
END AS [EmployerCode]
FROM [Records] AS [r]
LEFT JOIN [Ships] AS [r.Ship] ON [r].[ShipID] = [r.Ship].[ShipID]
LEFT JOIN [Jobsites] AS [r.Jobsite] ON [r].[JobsiteID] = [r.Jobsite].[JobsiteID]
LEFT JOIN [Sources] AS [r.Source] ON [r].[SourceID] = [r.Source].[SourceID]
LEFT JOIN [Witnesses] AS [r.Witness] ON [r].[WitnessID] = [r.Witness].[WitnessID]
LEFT JOIN [Defendants] AS [r.Contractor] ON [r].[ContractorID] = [r.Contractor].[DefendantID]
LEFT JOIN [Defendants] AS [r.Employer] ON [r].[EmployerID] = [r.Employer].[DefendantID]
LEFT JOIN (
SELECT [rp].[RecordID]
FROM [Records_Products] AS [rp]
INNER JOIN [Product_Defendant] AS [rp.ProductDefendant] ON [rp].[DefendantProductID] = [rp.ProductDefendant].[DefendantProductID]
INNER JOIN [Defendants] AS [rp.ProductDefendant.Defendant] ON [rp.ProductDefendant].[DefendantID] = [rp.ProductDefendant.Defendant].[DefendantID]
WHERE (
[rp.ProductDefendant.Defendant].[DefendantCode] LIKE (N'%' + 'cert') + N'%'
AND ([rp].[IsActive] = 1)
)
) AS RecordProduct ON [r].[RecordID] = RecordProduct.[RecordID]
WHERE ([r].[IsActive] = 1)
AND (
(
[r.Employer].[DefendantCode] LIKE (N'%' + 'cert') + N'%'
OR [r.Contractor].[DefendantCode] LIKE (N'%' + 'cert') + N'%'
)
OR RecordProduct.RecordID IS NOT NULL --OR EXISTS ( -- SELECT 1 -- FROM [Records_Products] AS [rp] -- INNER JOIN [Product_Defendant] AS [rp.ProductDefendant] ON [rp].[DefendantProductID] = [rp.ProductDefendant].[DefendantProductID] -- INNER JOIN [Defendants] AS [rp.ProductDefendant.Defendant] ON [rp.ProductDefendant].[DefendantID] = [rp.ProductDefendant.Defendant].[DefendantID] -- WHERE ([rp.ProductDefendant.Defendant].[DefendantCode] LIKE (N'%' + 'cert') + N'%' -- AND ([rp].[IsActive] = 1)) AND ([r].[RecordID] = [rp].[RecordID]) -- ) )) AS [t]ORDER BY [t].[SourceCode]OFFSET 0 ROWS FETCH NEXT 500 ROWS ONLY
)
)

Answer 1

The linq expression you supplied and the SQL generated do not match. For one, the linq expression is performing an Include on the various related tables which would have included all of those entity columns in the top-level SELECT which are not present in your example SQL. I also don't see conditions in the Linq expression for the Take 500 & OrderBy, or IsActive assertion on Record.
To be able to help determine the source of any performance concern we need to see the complete Linq expression and the resulting SQL.
Looking at the basis of the Linq expression you provided:
records = records
.Include(r => r.Employer)
.Include(r => r.Contractor)
.Include(r => r.RecordProducts)
.ThenInclude(rp => rp.ProductDefendant.Defendant)
.Where(r => EF.Functions.Like(r.Employer.DefendantCode, "%" + input.DefendantCode + "%")
|| EF.Functions.Like(r.Contractor.DefendantCode, "%" + input.DefendantCode + "%")
|| r.RecordProducts.Any(rp => EF.Functions.Like(rp.ProductDefendant.Defendant.DefendantCode, "%" + input.DefendantCode + "%") && rp.IsActive == true));
There are a few suggestions I can make:
There is no need for the Functions.Like. You should be able to achieve the same with Contains.
Avoid using Include and instead utilize Select to retrieve the columns from the resulting structure that you actually need. Populate these into ViewModels or consume them in the code. The less data you pull back, the better optimized the SQL can be for indexing, and the less data pulled across the wire. Consuming entities also leads to unexpected lazy-load scenarios as systems mature and someone forgets to Include a new relation.
.
records = records
.Where(r => r.IsActive
&& (r.Employer.DefendantCode.Contains(input.DefendantCode)
|| r.Contractor.DefendantCode.Contains(input.DefendantCode)
|| r.RecordProducts.Any(rp => rp.IsActive
&& rp.ProductDefendant.Defendant.DefendantCode.Contains(input.DefendantCode))
.OrderBy(r => r.SourceCode)
.Select(r => new RecordViewModel
{
// Populate the data you want here.
}).Take(500).ToList();
This also adds the IsActive check, OrderBy, and Take(500) based on your sample SQL.