Many of us sometimes get confused of different aspects of using IEnumerable<T> and IQueryable<T> in Entity Framework. One of considered opinions is that Entity Framework and DbContext and deffered execution just do all the magic and there is no difference. But even though LINQ query result remains basically the same, it may significantly impact the query performance.
Code sample
I'm going to create a simplified database consisting of one table with million records with Entity Framework Code First.
