title: How to show all invalid objects in PostgresQL
body: <p>Looking for the view I can list up all 'invalid' objects in PostgreSQL.
  In Oracle, we can use dab_objects.status column but I'm not sure if there is a simple way to do such a thing in PostgreSQL.</p>
  
  <p>Maybe, I can check the invalid indexes with below code.
  How can I do that for other objects?</p>
  
  <pre><code>SELECT pg_class.relname 
  FROM pg_class, pg_index 
  WHERE pg_index.indisvalid = false 
  AND pg_index.indexrelid = pg_class.oid;
  </code></pre>