How to eager fetch a child collection while joining child collection entities to an association

Answer 1

Fetching collections in the same query is almost never the best solution.

One of the best approaches is detailed in this link: http://ayende.com/Blog/archive/2010/01/16/eagerly-loading-entity-associations-efficiently-with-nhibernate.aspx

Personally, my preferred solution is to use batch-size in both the collections and the entities, set to the size of my default page length. That way, your query above would be done with 3 cheap, individually cacheable queries, instead of an expensive one.