 remote server if one is not already open corresponding to the current
   local transaction.  The remote transaction is committed or aborted when
   the local transaction commits or aborts.  Savepoints are similarly
   managed by creating corresponding remote savepoints.
  </p><p>
   The remote transaction uses <code class="literal">SERIALIZABLE</code>
   isolation level when the local transaction has <code class="literal">SERIALIZABLE</code>
   isolation level; otherwise it uses <code class="literal">REPEA