Parallel vs. serial independent node operations

gistfile1.js

// Serial, naive implementation
// one and two are not dependent on each other
db.read("SELECT ONE").done(function (one) {
    db.read("SELECT TWO").done(function (two) {
        emit(one, two);
    });
});

// Parallel
var async = require("async");
async.parallel([
    function (callback) {
        db.read("SELECT ONE").done(callback);
    },
    function (callback) {
        db.read("SELECT TWO").done(callback);
    }
], function (error, results) {
    emit(results[0], results[1]);
});