title: Explain "There can be many keys (and their associated values) in each partition, but the records for any given key are all in a single partition"
body: <p>"There can be many keys (and their associated values) in each partition, but the records for any given key are all in a single partition." This is a line of a famous hadoop text book. I am not getting the entire meaning of the second part of it which says "but the records for any given key are all in a single partition." Is this mean that all the records for a single key should be in a single partition or something else.</p>