Method prepare_index_key_scan_map

sql/handler.h:3722–3726

  /* This is called after index_init() if we need to do a index scan */
  virtual int prepare_index_scan() { return 0; }
  virtual int prepare_index_key_scan_map(const uchar * key, key_part_map keypart_map)
  {
    uint key_len= calculate_key_len(table, active_index, key, keypart_map);
    return  prepare_index_key_scan(key, key_len);
  }
  virtual int prepare_index_key_scan( const uchar * key, uint key_len )
  { return 0; }
  virtual int prepare_range_scan(const key_range *start_key, const key_range *end_key)