Entity-framework code is slow when using Include() many times

Question

I have been debugging some slow code and it seems that the culprit is the EF code posted below. It takes 4-5 seconds when the query is evaluated at a later stage. I\'m tryin

Answer 1

I've got a similar issue with a query that had 15+ "Include" statements and generated a 2M+ rows result in 7 minutes.

The solution that worked for me was:

1. Disabled lazy loading
2. Disabled auto detect changes
3. Split the big query in small chunks

A sample can be found below:

public IQueryable PerformQuery(int id) 
{
 ctx.Configuration.LazyLoadingEnabled = false;
 ctx.Configuration.AutoDetectChangesEnabled = false;

 IQueryable customObjectQueryable = ctx.CustomObjects.Where(x => x.Id == id);

 var selectQuery = customObjectQueryable.Select(x => x.YourObject)
                                                  .Include(c => c.YourFirstCollection)
                                                  .Include(c => c.YourFirstCollection.OtherCollection)
                                                  .Include(c => c.YourSecondCollection);

 var otherObjects = customObjectQueryable.SelectMany(x => x.OtherObjects);

 selectQuery.FirstOrDefault();
 otherObjects.ToList();

 return customObjectQueryable;
 }

IQueryable is needed in order to do all the filtering at the server side. IEnumerable would perform the filtering in memory and this is a very time consuming process. Entity Framework will fix up any associations in memory.