title: Incorrect key file for table MYSQL
body: <p>When i want to GROUP BY a query i get this error message:</p>
  
  <pre><code>Incorrect key file for table '/tmp/#sql_623d_0.MYI'; try to repair it
  </code></pre>
  
  <p>It is an InnoDB table with 3.000.000 records and 4,3 GiB large. </p>
  
  <p>When I run</p>
  
  <pre><code>repair table mytablename
  </code></pre>
  
  <p>I get this message:</p>
  
  <pre><code>The storage engine for the table doesn't support repair
  </code></pre>
  
  <p>Optimize won't work. What to do? </p>