parallel_connections.js

var db1 = initialize_connection_1();
var db2 = initialize_connection_2();
http.createServer(function (request, response) {
  var all_results = [];
  var replied = false;

  var try_reply = function(result, force) {
    all_results.push(result);
    if (!replied && (all_results.length == 2 || force)) {
      replied = true;
      response.end(render(all_results));
      clearTimeout(timeout);
    }
  }

  var timeout = setTimeout(function() {
    try_reply(null, true);
  }, 500);


  db1.query('select * from transactions where ...', function(results) {
     try_reply(results);
  });
  db2.query('select * from profiles where ...', function(results) {
    try_reply(results);
  });
  
}).listen(8124);