map_reduce_example.js

// http://docs.mongodb.org/manual/core/map-reduce/
// $ tail -f /var/log/mongodb/mongodb.log

var map = function(){
  print("map");
  emit(1, 2);
};
var reduce = function(key, values){
  print("reduce");
  return Array.sum(values);
};
db.submissions.mapReduce(map, reduce, { out: 'foobar'} );