title: Sum multiple metrics without summing over a wildcard?
body: <p>I have the following metrics:</p>
  
  <ul>
  <li><code>folsomite.&lt;host&gt;.cache.hit1</code></li>
  <li><code>folsomite.&lt;host&gt;.cache.hit2</code></li>
  <li><code>folsomite.&lt;host&gt;.cache.miss1</code></li>
  <li><code>folsomite.&lt;host&gt;.cache.miss2</code></li>
  <li><code>folsomite.&lt;host&gt;.cache.miss3</code></li>
  </ul>
  
  <p><em>(The caching library I'm using has 2 flavours of hit: first-chance and second-chance, and 3 flavours of miss)</em></p>
  
  <p>And I want to calculate <code>(hit1 + hit2) / (miss1 + miss2 + miss3)</code>. I thought I'd start by calculating <code>(hit1 + hit2)</code>, but if I use <code>sumSeries</code> as <code>sumSeries(folsomite.*.cache.hit*)</code>, then it sums over the <code>&lt;host&gt;</code> values as well.</p>
  
  <p>How do I sum multiple metrics over some wildcards, without summing over other wildcards? Or how do I specifically add two (or more metrics), while preserving the wildcards?</p>
  
  <p>And, having done that, can I divide one (summed) result by another?</p>
  
  <p><strong>Edit:</strong> I'm actually using grafana to render the graphs. Does that make a difference?</p>