private static StructLikeMap<Long> readWithLegacy(
      UnkeyedTable table, Long snapshotId, String type) {
    if (snapshotId == null) {
      Snapshot snapshot = table.currentSnapshot();
      if (snapshot == null) {
        return readLegacyPartitionProperties(table, type);
      } else {
        snapshotId = snapshot.snapshotId();
      }
    }
    StructLikeMap<Long> result = readFromStatisticsFile(table, snapshotId, type);
    return result != null ? result : readLegacyPartitionProperties(table, type);
  }
Return the table root location of the mixed-format table.
amoro-format-iceberg/src/main/java/org/apache/amoro/utils/MixedTableUtil.java