title: What NoSQL DB to use for sparse Time Series like data?
body: <p>I'm planning a side project where I will be dealing with Time Series like data and would like to give one of those shiny new NoSQL DBs a try and am looking for a recommendation.</p>
  
  <p>For a (growing) set of <code>symbols</code> I will have a list of (<code>time</code>,<code>value</code>) tuples (increasing over time).
  Not all <code>symbols</code> will be updated; some <code>symbols</code> may be updated while others may not, and completely new <code>symbols</code> may be added.</p>
  
  <p>The database should therefore allow:</p>
  
  <ul>
  <li>Add Symbols with initial one-element (tuple) list. E.g. A: [(2012-04-14 10:23, 50)]</li>
  <li>Update Symbols with a new tuple. (Append that tuple to the list of that symbol).</li>
  <li>Read the data for a given symbol. (Ideally even let me specify the time frame for which the data should be returned)</li>
  </ul>
  
  <p>The create and update operations should possibly be atomic. If reading multiple symbols at once is possible, that would be interesting.</p>
  
  <p>Performance is not critical. Updates/Creates will happen roughly once every few hours. </p>