title: Prometheus metric and label naming for high cardinality dimensions
body: <p>I want to report a metric for each item that is viewed in our system. We have tens of millions of items.</p>
  
  <p>In the Prometheus documentation it warns not to label high cardinality metrics</p>
  
  <blockquote>
    <blockquote>
      <p>CAUTION: Remember that every unique combination of key-value label pairs represents a new time series, which can dramatically increase the amount of data stored. Do not use labels to store dimensions with high cardinality (many different label values), such as user IDs, email addresses, or other unbounded sets of values.</p>
    </blockquote>
  </blockquote>
  
  <p>So in this case what is the best practice?</p>