code: func LoadCMSketchWithTopN(exec sqlexec.RestrictedSQLExecutor, tableID, isIndex, histID int64, cms []byte) (*CMSketch, error) {
  	sql := fmt.Sprintf("select HIGH_PRIORITY value, count from mysql.stats_top_n where table_id = %d and is_index = %d and hist_id = %d", tableID, isIndex, histID)
  	topNRows, _, err := exec.ExecRestrictedSQL(nil, sql)
  	if err != nil {
  		return nil, err
  	}
  	topN := make([]*TopNMeta, 0, len(topNRows))
  	for _, row := range topNRows {
  		topN = append(topN, &TopNMeta{Data: row.GetBytes(0), Count: row.GetUint64(1)})
  	}
  	return decodeCMSketch(cms, topN)
  }
docs: // LoadCMSketchWithTopN loads the CM sketch with topN from storage.