The crux of the change is to try and make the queries simpler and pull
out fewer rows. Before, there were quite a few joins against subqueries,
which caused postgres to pull out more rows than necessary.

Instead, let's simplify the query and do some of the filtering out in
Python instead, letting Postgres do better optimizations now that it
doesn't have to deal with joins against subqueries.

Co-authored-by: Andrew Morgan <[email protected]>

Co-authored-by: Andrew Morgan <[email protected]>