I've got a directory with a bunch of MapReduce data in it. I want to know how many <Key, Value> pairs it contains. I could write a mapper-only process that takes <Writeable, Writeable> pairs as input and updates a counter, but it seems like this utility should already exist. Does it, or do I have to roll my own?
Bonus question, is there a way to count the number of <Key, Value> pairs without deserializing the values? This can be expensive for the data I'm working with.
