title: I need to know the list of tables on which there are locks currently
body: <pre><code>select 
    A.table_id, 
    last_update, 
    last_commit, 
    lock_owner_pid, 
    lock_status,
    B.table
  from stv_locks as A left outer join svv_table_info as B on A.table_id = B.table_id
  order by last_update asc
  </code></pre>
  
  <p>I used the query above, but am getting <code>null</code> in a name for some <code>table_ids</code>. what are these? </p>