Still slow with id prefix based paging

45s to pull back 2k records, seems ridiculously slow

may need to try skip/limit even though it's not scalable
Switch to dumb query, much faster

Ran through 8850000 records in 3036.39569712 s

try $nin with dumb query. Might be better.
use $nin in query - about 10% faster

Ran through the 8.85M records in 2709.53324914