Express + Passport + Session. Executes a query for every page load

I'm using Express 4.2.0 with passport 0.2.0.

The express-session middleware that I am using is 1.2.1

I'm relatively new to node authentication so please bear with me.

I noticed that for everyone page load, passport is executing a db request:

Executing (default): SELECT * FROM "users" WHERE "users"."user_id"=7 LIMIT 1;

This doesn't make sense to me as I would think that the user has already been authenticated and serialized. And the session is now stored in the browser cookie. I also checked that I do have a cookie session stored in my browser.

Here are my app.js configuration:

var express = require('express');
var path = require('path');
var favicon = require('static-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
//var sys = require('sys');
var cons = require('consolidate');

/* sequelize */
var db = require('./models'); 

/* passport and its friends */
var passport = require('passport');
var flash = require('connect-flash');
var session = require('express-session');

/* routes */
var routes = require('./routes/index');
var users = require('./routes/users');


//filesystem middleware
//var fs = require('fs');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.engine('dust', cons.dust);
app.set('view engine', 'dust');

app.use(favicon());
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded());
app.use(cookieParser('hashionhashion'));
app.use(require('less-middleware')(path.join(__dirname, 'public')));
app.use(express.static(path.join(__dirname, 'public')));

app.use(session({ secret: 'hashionhashion' })); // session secret
app.use(passport.initialize());
app.use(passport.session()); // persistent login sessions
app.use(flash()); // use connect-flash for flash messages stored in session

//routing
app.use('/', routes);
app.use('/users', users);

and here is the passport serialize/deserialize function:

passport.serializeUser(function(user, done) {
    done(null, user.user_id);
});

// used to deserialize the user
passport.deserializeUser(function(id, done) {
    db.User.find({ where: {user_id: id} }).success(function(user){
        done(null, user);
      }).error(function(err){
        done(err, null);
      });
});