How to deal with large result sets with Linq to Entities?

Question

I have a fairly complex linq to entities query that I display on a website. It uses paging so I never pull down more than 50 records at a time for display.

But I also wa

Answer 1

Look at the return value of the LINQ query. It should be IEnumerable<>, which only loads one object at a time. If you then use something like .ToList(), they will all be loaded into memory. Just make sure your code doesn't maintain a list or use more than one instance at a time and you will be fine.

Edit: To add on to what people have said about foreach... If you do something like:

var query = from o in Objects
            where o.Name = "abc"
            select o;

foreach (Object o in query)
{
   // Do something with o
}

The query portion uses deferred execution (see examples), so the objects are not in memory yet. The foreach iterates through the results, but only getting one object at a time. query uses IEnumerator, which has Reset() and MoveNext(). The foreach calls MoveNext() each round until there are no more results.