code: @Override
      public RowIterator findFirstRow(Session session, PersistentStore store,
                                      Object[] rowdata, int match) {
  
          NodeAVL node = findNode(session, store, rowdata, defaultColMap, match);
  
          return getIterator(session, store, node);
      }
docs: Return the first node equal to the indexdata object. The rowdata has
  the same column mapping as this index.
  
  @param session session object
  @param store store object
  @param rowdata array containing index column data
  @param match count of columns to match
  @return iterator