Question

I was doing some testing and straight LINQ-to-SQL queries run at least 80% faster than if calling stored procedures via the LINQ query

In SQL Server profiler a generic LINQ query

 var results = from m in _dataContext.Members  select m; 

took only 19 milliseconds as opposed to a stored procedure

 var results = from m in _dataContext.GetMember(userName)  select m; 

(GetMember being the stored procedure) doing the same query which took 100 milliseconds

Why is this?

Edit:

The straight LINQ looks like this in Profiler

SELECT      [t1].[MemberID], [t1].[Aspnetusername], [t1].[Aspnetpassword],      [t1].[EmailAddr], [t1].[DateCreated],      [t1].[Location], [t1].[DaimokuGoal], [t1].[PreviewImageID],        [t1].[value] AS [LastDaimoku],      [t1].[value2] AS [LastNotefied],      [t1].[value3] AS [LastActivityDate], [t1].[IsActivated] FROM      (SELECT           [t0].[MemberID], [t0].[Aspnetusername], [t0].[Aspnetpassword],           [t0].[EmailAddr], [t0].[DateCreated], [t0].[Location],           [t0].[DaimokuGoal], [t0].[PreviewImageID],           [t0].[LastDaimoku] AS [value], [t0].[LastNotefied] AS [value2],           [t0].[LastActivityDate] AS [value3], [t0].[IsActivated]      FROM           [dbo].[Members] AS [t0]) AS [t1] WHERE      [t1].[EmailAddr] = @p0 

The stored procedure is this

SELECT Members.* FROM Members  WHERE dbo.Members.EmailAddr = @Username 

So you see the stored procedure query is much simpler.. but yet its slower…. makes no sense to me.

Answer 1

1) Compare like with like. Perform exactly the same operation in both cases, rather than fetching all values in one case and doing a query in another.

2) Don’t just execute the code once – do it lots of times, so the optimiser has a chance to work and to avoid one-time performance hits.

3) Use a profiler (well, one on the .NET side and one on the SQL side) to find out where the performance is actually differing.