title: What are Redis "out_" prefix keys?
body: <p>I am seeing multiple out_ prefix keys in  my Redis ( version 3+ ) . Can any one help me understand these keys ? Are these internal , temporary keys ?</p>
  
  <p>The application does not create these keys .</p>
  
  <pre><code>[02.66%] Biggest zset   found so far 'out_GVwthhmz' with 765025 members
  [09.91%] Biggest zset   found so far 'out_JIwnd8Cu' with 798580 members
  [69.70%] Biggest zset   found so far 'out_UcP6p4YL' with 801308 members
  </code></pre>
  
  <p>Thanks</p>