node-mysql pool

var mysql = require('mysql');
var pool  = mysql.createPool(config);

pool.getConnection(function(err, connection) {
  // Use the connection
  connection.query( 'SELECT something FROM sometable', function(err, rows) {
    // And done with the connection.
    connection.end();

    // Don't use the connection here, it has been returned to the pool.
  });
});