title: Large document vs many documents
body: <p>Just wanted an opinion, or at least a rule of thumb over which is better in a database structure for CouchDB. Is it better to have all related data for an item in a single document, or have parts of all items in many documents?</p>
  
  <p>Let me illustrate what I mean by giving you an example. I currently log 4 events from our system, at 1 minute intervals, lets call them event_1, event_2, event_3 and even_4. Data is stored for each of the 4 events, regardless of value (you'll always get a value, even if everything is okay).</p>
  
  <p><strong>Option 1:</strong> Group events, and append new timestamp/values to the document...</p>
  
  <pre><code>{
      event_1: [ 
          { timestamp, value },
          { timestamp, value },
          { timestamp, value },
          ...etc
      ]
  },
  {
      event_2: [ 
          { timestamp, value },
          { timestamp, value },
          { timestamp, value },
          ...etc
      ]
  },
  {
      event_3: [ 
          { timestamp, value },
          { timestamp, value },
          { timestamp, value },
          ...etc
      ]
  }
  ...etc
  </code></pre>
  
  <p><strong>Option 2:</strong> Keep a huge list of documents, with the latest values (which is how they're actually delivered from the system)?</p>
  
  <pre><code>{
      timestamp: {
          { event_1, value },
          { event_2, value },
          { event_3, value },
          { event_4, value }
      }
  },
  {
      timestamp: {
          { event_1, value },
          { event_2, value },
          { event_3, value },
          { event_4, value }
      }
  },
  {
      timestamp: {
          { event_1, value },
          { event_2, value },
          { event_3, value },
          { event_4, value }
      }
  }
  ...etc
  </code></pre>
  
  <p>I'm currently using the 2nd option, but was just curious to see peoples opinions on what would be considered best practice...I'm starting to think that Option 1 might be better, as the way i am reporting, results are grouped by event (shown in line graph of each event).</p>