?

db.runCommand(

{ mapreduce : <collection>,

? ?map : <mapfunction>,

? ?reduce : <reducefunction>

? ?[, query : <query filter object>]

? ?[, sort : <sorts the input objects using this key. Useful for optimization, like sorting by the emit key for fewer reduces>]

? ?[, limit : <number of objects to return from collection>]

? ?[, out : <see output options below>]

? ?[, keeptemp: <true|false>]

? ?[, finalize : <finalizefunction>]

? ?[, scope : <object where fields go into javascript global scope >]

? ?[, verbose : true]

}

);

?