presto-hive/src/main/java/io/prestosql/plugin/hive/statistics/MetastoreHiveStatisticsProvider.java/MetastoreHiveStatisticsProvider/getDistinctValuesCount
class MetastoreHiveStatisticsProvider:    private static OptionalLong getDistinctValuesCount(HiveColumnStatistics statistics)
    {
        if (statistics.getBooleanStatistics().isPresent() &&
                statistics.getBooleanStatistics().get().getFalseCount().isPresent() &&
                statistics.getBooleanStatistics().get().getTrueCount().isPresent()) {
            long falseCount = statistics.getBooleanStatistics().get().getFalseCount().getAsLong();
            long trueCount = statistics.getBooleanStatistics().get().getTrueCount().getAsLong();
            return OptionalLong.of((falseCount > 0 ? 1 : 0) + (trueCount > 0 ? 1 : 0));
        }
        if (statistics.getDistinctValuesCount().isPresent()) {
            return statistics.getDistinctValuesCount();
        }
        return OptionalLong.empty();
    }