Shows issue using transactions on the same db connection

app.js

var http = require('http');
var mysql = require('mysql');

var db = mysql.createClient({
	user: 'root',
	password: 'password',
	database: 'db1'
});

db.query("BEGIN"); // Start first transaction
db.query("INSERT test (val) VALUES ('foo')"); // Do stuff in transaction
// Wait 10 seconds
setTimeout(function(){
	db.query("ROLLBACK"); // End transaction cancelling all changes with a rollback
	console.log('ROLLBACK first transaction');
}, 10000);

http.createServer(function (req, res) {
	if (req.url == '/')
	{
		var db = mysql.createClient({
			user: 'root',
			password: 'password',
			database: 'db1'
		});
		db.query("BEGIN"); // Start new transaction
		db.query("INSERT test (val) VALUES ('bar')"); // Do stuff
		db.query("COMMIT"); // Commit changes

		// Select all data from test table. It should only show the 'bar' record.
		db.query("SELECT * FROM test", function(err, results, fields) {
			res.writeHead(200, {'Content-Type': 'text/plain'});
			res.end(JSON.stringify(results));
		});		
	}
}).listen(3000, 'localhost');

test-table-structure.sql

delimiter $$

CREATE TABLE `test` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `val` varchar(45) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=18 DEFAULT CHARSET=latin1$$

The issue with the code now is that http.createServer's callback function get's called twice per request sometimes. This is causing two records to be inserted per request. How do I prevent this from happening?

Multiple request problem had to do with /favicon.ico being requested after page request.