EntityFramework LINQ query count fails but query returns result. How to optimize LINQ query?

Question

I have the below LINQ query that performs a self-left-outer-join. The querys looks a little complex but is simply doing a self join on itself(purpose if to join each record with

Answer 1

You can simply use AsParallel() to enable multithreading execution of the linq query. You should then check your tables' indexes to improve performances.