What is the difficulties in choosing views to materialize?
Materializing views is to speed up the on-line query (described in previous question). However, materializing all views takes up space, and the update of view also takes times. So, this is the question of how to optimize the query time with a space and update time constraint. Moreover, some views can be computed from other views quickly, we also need to avoid such views as materializing it give little benefits to us.
