code: @Override
      public void rollback(final Xid _xid)
      {
          if (JDBCStoreResource.LOG.isDebugEnabled()) {
              JDBCStoreResource.LOG.debug("rollback (xid = " + _xid + ")");
          }
      }
docs: If the file written in the virtual file system must be rolled back, only
  the created temporary file (created from method {@link #write}) is
  deleted.
  
  @param _xid  global transaction identifier (not used, because each file
  with the file id gets a new VFS store resource instance)