title: Understanding situation with multiple overlapping indexes in oracle
body: <p>Given the following indexes for an Oracle database:</p>
  
  <pre><code>CREATE INDEX subject_x1 ON subject (code);
  CREATE INDEX subject_x2 ON subject (code, status);
  </code></pre>
  
  <p>Is it true that the first index is redundant, and can be removed. We need to get this right as this is a relatively large sized table that is going to be constantly hammered.</p>
  
  <p>Any oracle documentation explaining or confirming this would be very helpful.</p>