title: Redis / Get all keys & values from redis with prefix
body: <p>I store my data in redis. I store in one raw it guid, createday, and it size.</p>
  
  <p>So I define the following:</p>
  
  <pre><code>var dbclient1 = db.createClient();
  dbclient1.hmset("doc:3743-da23-dcdf-3213", "date", "2015-09-06 00:00:01", "size", "203")
  dbclient1.zadd("cache", 32131, "37463-da23-dcdf-3213")
  </code></pre>
  
  <p>I wish to view all my files in my db. So I try the following: </p>
  
  <pre><code>dbclient1.hgetall("doc:*", function (err, res){
          console.log(err)
          console.log(res)
  })
  </code></pre>
  
  <p>but res is <code>undefined</code>. How can I do it?</p>