Looking for a implementation solution for a pattern, whose name I don't know yet !!!

games.js

----------------- Formation of a game----------------------
db.games.save({
	"_id" : ObjectId("4ddf595fb57f547120000002")
	"pi" : "3831F237040C4BC083420EE4EC5FAE85",
        "di" : "76280583D2DA4903A0336C85AA3B3DE8468E21F8",
	"np" : 92,
	"p1" : "n",
});
----------------- Formation of a game ends-----------------

-----------Map Reduce Operation-------------------------------------
// Step 2 :
// Update all the "not processed" games to "in process". 
// 
db.games.update({p1:"n"},{$set:{p1:"i"}},false,true); 
 
//
// The map function
//
var map_players_points_total = function() {
      emit(this.pi, {np: this.np, di: this.di});
    };

//
// The reduce function, add up all the points for each key (here player).
//
var reduce_players_points_total = function(key,values){
    total_points_gained = 0;
    device_id = values[0].di;
    values.forEach(function(i){
        total_points_gained += i.np;
    });
    return {np:total_points_gained, di: device_id };
};

// Step 3 and 4 :
// Performing map-reduce.
// Note that 'out' type is set to "reduce".
// 'query' is only to select those games that have been marked as "in process" using p1 field.
// Those fulfilling the criteria are given to map function as input.
// Once they have been performed upon, they are marked to "yes, processed", in next statment.
// 
var result_players_points_total = db.games.mapReduce(map_players_points_total                       //Step 4
                                                        ,reduce_players_points_total
                                                        ,{
                                                          query:{p1:"i"}                            // Step 3 
                                                         ,out: {reduce:"players_points_total"}
                                                        });

// Step 5:
// Update all the "in process" games to "yes, processed" . 
// 
db.games.update({p1:"i"},{$set:{p1:"y"}},false,true); 
-----------Map Reduce Operation Ends -------------------------------------