presto-hive/src/main/java/io/prestosql/plugin/hive/util/Statistics.java/Statistics/getPartitionValues
class Statistics:    private static List<String> getPartitionValues(ComputedStatistics statistics, List<String> partitionColumns, List<Type> partitionColumnTypes)
    {
        checkArgument(statistics.getGroupingColumns().equals(partitionColumns),
                "Unexpected grouping. Partition columns: %s. Grouping columns: %s", partitionColumns, statistics.getGroupingColumns());
        Page partitionColumnsPage = new Page(1, statistics.getGroupingValues().toArray(new Block[] {}));
        return createPartitionValues(partitionColumnTypes, partitionColumnsPage, 0);
    }