private static int daysFromTimestamp(Timestamp timestamp) {
    return DateTimeUtil.daysFromDate(timestamp.toLocalDateTime().toLocalDate());
  }
In the partition path hours are represented as year-month-day-hour, e.g.
1970-01-01-01. We need to convert it to a single integer which represents the hours
from '1970-01-01 00:00:00'.
iceberg/iceberg-handler/src/main/java/org/apache/iceberg/mr/hive/HiveIcebergFilterFactory.java