Establish Pool Connection in node-mysql

Try this:

function Pool(num_conns)
{
    this.pool = [];
    for(var i=0; i < num_conns; ++i)
        this.pool.push(createConnection()); // your new Client + auth
    this.last = 0;
}

Pool.prototype.get = function()
{
    var cli = this.pool[this.last];
    this.last++;
    if (this.last == this.pool.length) // cyclic increment
       this.last = 0;
    return cli;
}