Attempt #1: Store & aggregate Document for each list item, timestamp and site Aggregation framework: match, group, sort Collection per list type Flexible Made app simpler Huge number of documents Slow aggregate queries: ~1s+ ✔ ✔ X X
Attempt #2 Document per list, timestamp and site Collection per list type Faster lookups (no aggregation) Fewer documents Smaller _id Document size limit Unordered High data transfer ✔ ✔ ✔ X X X