vibhatha commented on a change in pull request #11911:
URL: https://github.com/apache/arrow/pull/11911#discussion_r770214661
##########
File path: python/pyarrow/tests/test_dataset.py
##########
@@ -3621,6 +3621,204 @@ def compare_tables_ignoring_order(t1, t2):
assert not extra_file.exists()
+def _generate_random_int_array(size=4, min=1, max=10):
+ return np.random.randint(min, max, size)
+
+
+def _generate_data_and_columns(num_of_columns, records_per_row,
+ unique_records=None):
+ data = []
+ column_names = []
+ if unique_records is None:
+ unique_records = records_per_row
+ for i in range(num_of_columns):
+ data.append(_generate_random_int_array(size=records_per_row,
+ min=1,
+ max=unique_records))
+ column_names.append("c" + str(i))
+ return data, column_names
+
+
+def _get_num_of_files_generated(base_directory):
+ file_dirs = os.listdir(base_directory)
+ number_of_files = 0
+ for _, file_dir in enumerate(file_dirs):
+ sub_dir_path = base_directory / file_dir
+ number_of_files += len(os.listdir(sub_dir_path))
+ return number_of_files
+
+
+def _get_compare_pair(data_source, record_batch):
+ num_of_files_generated = _get_num_of_files_generated(
+ base_directory=data_source)
+ number_of_unique_rows = len(pa.compute.unique(record_batch[0]))
+ return num_of_files_generated, number_of_unique_rows
+
+
+def test_write_dataset_max_rows_per_file(tempdir):
+ directory = tempdir / 'ds'
+ max_rows_per_file = 10
+ max_rows_per_group = 10
+ num_of_columns = 2
+ records_per_row = 35
+
+ data, column_names = _generate_data_and_columns(num_of_columns,
+ records_per_row)
+
+ record_batch = pa.record_batch(data=data, names=column_names)
+
+ sub_directory = directory / 'onewrite'
+
+ ds.write_dataset(record_batch, sub_directory, format="parquet",
+ max_rows_per_file=max_rows_per_file,
+ max_rows_per_group=max_rows_per_group)
+
+ files_in_dir = os.listdir(sub_directory)
+
+ # number of partitions with max_rows and the partition with the remainder
+ expected_partitions = len(data[0]) // max_rows_per_file + 1
+ expected_row_combination = [max_rows_per_file
+ for i in range(expected_partitions - 1)] \
+ + [len(data[0]) - ((expected_partitions - 1) * max_rows_per_file)]
+
+ # test whether the expected amount of files are written
+ assert len(files_in_dir) == expected_partitions
+
+ # compute the number of rows per each file written
+ result_row_combination = []
+ for _, f_file in enumerate(files_in_dir):
+ f_path = sub_directory / str(f_file)
+ dataset = ds.dataset(f_path, format="parquet")
+ result_row_combination.append(dataset.to_table().shape[0])
+
+ # test whether the generated files have the expected number of rows
+ assert len(expected_row_combination) == len(result_row_combination)
+ assert sum(expected_row_combination) == sum(result_row_combination)
+
+
+def test_write_dataset_min_rows_per_group(tempdir):
+ directory = tempdir / 'ds'
+ min_rows_per_group = 10
+ max_rows_per_group = 20
+ num_of_columns = 2
+ records_per_row = 49
+ unique_records = 5
+
+ data, column_names = _generate_data_and_columns(num_of_columns,
+ records_per_row,
+ unique_records)
+
+ record_batch = pa.record_batch(data=data, names=column_names)
+
+ data_source = directory / "min_rows_group"
+
+ ds.write_dataset(data=record_batch, base_dir=data_source,
+ min_rows_per_group=min_rows_per_group,
+ max_rows_per_group=max_rows_per_group,
+ format="parquet")
+
+ files_in_dir = os.listdir(data_source)
+ batched_data = []
+ for _, f_file in enumerate(files_in_dir):
+ f_path = data_source / str(f_file)
+ dataset = ds.dataset(f_path, format="parquet")
+ table = dataset.to_table()
+ batches = table.to_batches()
+ for batch in batches:
+ batched_data.append(batch.num_rows)
+
+ assert batched_data[0] > min_rows_per_group and \
+ batched_data[0] <= max_rows_per_group
+ assert batched_data[1] > min_rows_per_group and \
+ batched_data[1] <= max_rows_per_group
+ assert batched_data[2] <= max_rows_per_group
+
+
+def test_write_dataset_max_rows_per_group(tempdir):
+ directory = tempdir / 'ds'
+ max_rows_per_group = 18
+ num_of_columns = 2
+ records_per_row = 30
+ unique_records = 5
+
+ data, column_names = _generate_data_and_columns(num_of_columns,
+ records_per_row,
+ unique_records)
+
+ record_batch = pa.record_batch(data=data, names=column_names)
+
+ data_source = directory / "max_rows_group"
+
+ ds.write_dataset(data=record_batch, base_dir=data_source,
+ max_rows_per_group=max_rows_per_group,
+ format="parquet")
+
+ files_in_dir = os.listdir(data_source)
+ batched_data = []
+ for _, f_file in enumerate(files_in_dir):
+ f_path = data_source / str(f_file)
+ dataset = ds.dataset(f_path, format="parquet")
+ table = dataset.to_table()
+ batches = table.to_batches()
+ for batch in batches:
+ batched_data.append(batch.num_rows)
+
+ assert batched_data == [18, 12]
+
+
+def test_write_dataset_max_open_files(tempdir):
+ # TODO: INCOMPLETE TEST CASE WIP
+ directory = tempdir / 'ds'
+ print("Directory : ", directory)
+
+ record_batch_1 = pa.record_batch(data=[[1, 2, 3, 4, 0],
+ ['a', 'b', 'c', 'd', 'e']],
+ names=['c1', 'c2'])
+ record_batch_2 = pa.record_batch(data=[[5, 6, 7, 8, 0],
+ ['a', 'b', 'c', 'd', 'e']],
+ names=['c1', 'c2'])
+ record_batch_3 = pa.record_batch(data=[[9, 10, 11, 12, 0],
+ ['a', 'b', 'c', 'd', 'e']],
+ names=['c1', 'c2'])
+ record_batch_4 = pa.record_batch(data=[[13, 14, 15, 16, 0],
+ ['a', 'b', 'c', 'd', 'e']],
+ names=['c1', 'c2'])
+
+ table = pa.Table.from_batches([record_batch_1, record_batch_2,
+ record_batch_3, record_batch_4])
+
+ partitioning = ds.partitioning(
+ pa.schema([("c2", pa.string())]), flavor="hive")
+
+ data_source_1 = directory / "default"
+
+ ds.write_dataset(data=table, base_dir=data_source_1,
+ partitioning=partitioning, format="parquet")
+
+ # CASE 1: when max_open_files=default & max_open_files >= num_of_partitions
+ # the number of unique rows must be equal to
+ # the number of files generated
Review comment:
I think there is a misinterpretation in the comment and I haven't
completely documented the statement. It must be
```python
# CASE 1: when max_open_files=default & max_open_files >=
num_of_partitions
# In case of a writing to disk via partitioning based on a particular
column (considering row labels in that column),
# the number of unique rows must be equal to the number of files
generated
```
Do you think this is appropriate?
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