In a word, yes.
The data is filtered and processed at multiple stages, that is part of why the system is setup in a tiered architecture.
The actual data that turns into a visual result (graph) is fairly small after all the stages are complete. It is like mining for diamonds where you discard almost everything you pull from the ground and keep only the smallest portion.
After all, if the problem was easy there would be no need for all of this computing to be thrown at it.