For map-reduce implementation, see A Structure in programming languages that associate keys with values, where keys may nest other pairs of keys and values (e.g.dictionaries, hashes, maps, and associative arrays). The properties of these structures depend on the language specification and implementation.
Mongo DB does not permit the exterior ring to self-intersect.
Interior rings must be fully contained within the outer loop and cannot intersect or overlap with each other.
A padding factor of 1 means that Mongo DB will allocate only the amount of space needed for the document.
A padding factor of 2 means that Mongo DB will allocate twice the amount of space required by the document.
Chunk ranges are inclusive of the lower boundary and exclusive of the upper boundary.