If you are experiencing performance issues with Entity Framework Core 1.0 when you try to include related objects in your LINQ and lambda expressions on record sets of just a few thousand records, (More about Lazy and Eager Loading here) then check out these examples on how to improve it. Of the many ways, the best way that I have found to negate those performance problems and to optimize your requests is by using .AsNoTracking()
What is AsNoTracking()
When you use .AsNoTracking() you are basically telling the context not to track the retrieved information. Sure, this turns off a useful EF feature, but in many cases (like building an api in my case) this feature is unneeded.
In summary, Tracking is turned on by default and is great if you want to retrieve and save objects all within the same context. But if this is not required, you should use AsNewTracking(). AsNoTracking() decouples the returned records from the context, making your queries much faster!
IList<Player> playerList = db.Player.AsNoTracking().ToList()
Example with Joins
IList<Player> playerList = (from p in db.Player select p) .Include(p => p.Team) .ThenInclude(t => t.League) .AsNoTracking() .ToList();
It is also worth noting that there is another way to decouple your objects from EF. This other way can be done by adding .AsEnumerable(). That would look like this:
var decoupledList = from x in TableA<strong>.AsEnumerable()</strong>