title: EF Core 3.0 .Include does not work as expected and Super Slow
body: <p>I have linq query like this in EF Core 2.0, It work as it is, but when I upgrade to EF Core 3.0 it always timeout. I found the issue in <code>query = query.Where(x =&gt; x.Questions);</code>.<br/>
  My Question is i would like to return the course with filter questions like only Take(10) or with .Where condition that only display certain range not all questions.</p>
  
  <pre><code>var query = _courseRepository.Table;
  query = query.Where(x =&gt; x.Id == id);
  query = query.Include(x =&gt; x.Questions);
  query = query.Include(x =&gt; x.CourseYear);
  query = query.Include(x =&gt; x.CourseSubject);
  query = query.Include(x =&gt; x.Instructors).ThenInclude(y =&gt; y.User);
  query = query.Include(x =&gt; x.Instructors).ThenInclude(y =&gt; y.Course);
  query = query.Include(x =&gt; x.Instructors).ThenInclude(y =&gt; y.CourseClass);
  query = query.Include(x =&gt; x.CourseSections);
  query = query.Include(x =&gt; x.CourseSections).ThenInclude(y =&gt; y.Lessons);
  query = query.Include(x =&gt; x.CourseClasses);
  query = query.Include(x =&gt; x.UserCourses).ThenInclude(y =&gt; y.User);
  var result = query.FirstOrDefault();
  </code></pre>