[nawariata]

Does Rethink store keys with every record or uses more efficient mechanism?

[mrits]

While you could technically use JSON to have a more efficient storage I think it safe to assume they use Key/Value.

http://rethinkdb.com/docs/comparison-tables/

I can't believe new databases are still using this model. Some of my data storage would be 90% keys and 10% data as JSON.