Entity Framework Poor COUNT Performance

Question

We are experiencing very poor performance using Entity Framework 5.0 with MySql Connector 6.6.6.0 for count based queries. Our data structure looks like:

Table: P         


        

Answer 1

Testing with EF 6

db.Users.Count(u => u.LastName == "xyz")

and

db.Users.Where(u=>u.LastName=="xyz").Count()

produce identical sql queries.

SELECT 
[GroupBy1].[A1] AS [C1]
FROM ( SELECT 
    COUNT(1) AS [A1]
    FROM [dbo].[Users] AS [Extent1]
    WHERE N'xyz' = [Extent1].[LastName]
)  AS [GroupBy1]