presto-hive/src/main/java/io/prestosql/plugin/hive/BackgroundHiveSplitLoader.java/BackgroundHiveSplitLoader/getPartitionSchema
class BackgroundHiveSplitLoader:    private static Properties getPartitionSchema(Table table, Optional<Partition> partition)
    {
        if (!partition.isPresent()) {
            return getHiveSchema(table);
        }
        return getHiveSchema(partition.get(), table);
    }