H5Record
Large dataset ( > 100G, <= 1T) storage format for Pytorch (wip)
Support python 3
pip install h5record
Why?
-
Writing large dataset is still a wild west in pytorch. Approaches seen in the wild include:
- large directory with lots of small files : slow IO when complex file is fetched, deserialized frequently
- database approach : depend on what kind of database engine used, usually multi-process read is not supported
- the above method scale non linear in terms of data - storage size
-
TFRecord solved the above problems well ( multiprocess fetch, (de)compression ), fast serialization ( protobuf )
-
However TFRecord port does not support data size evaluation (used frequently by Dataloader ), no index level access available ( important for data evaluation or verification )
H5Record aim to tackle TFRecord problems by compressing the dataset into HDF5 file with an easy to use interface through predefined interfaces ( String, Image, Sequences, Integer).
Some advantage of using H5Record
-
Support multi-process read
-
Relatively simple to use and low technical debt
-
Support compression/de-compression on the fly
-
Quick load to memory if required
Simple usage
pip install h5record
- Sentence Similarity
from h5record import H5Dataset, Float, String
schema = (
String(name='sentence1'),
String(name='sentence2'),
Float(name='label')
)
data = [
['Sent 1.', 'Sent 2', 0.1],
['Sent 3', 'Sent 4', 0.2],
]
def pair_iter():
for row in data:
yield {
'sentence1': row[0],
'sentence2': row[1],
'label': row[2]
}
dataset = H5Dataset(schema, './question_pair.h5', pair_iter())
for idx in range(len(dataset)):
print(dataset[idx])
Note
Due to in progress development, this package should be use in care in storage with FAT, FAT-32 format
Comparison between different compression algorithm
No chunking is used
Compression Type | File size | Read speed row/second |
---|---|---|
no compression | 2.0G | 2084.55 it/s |
lzf | 1.7G | 1496.14 it/s |
gzip | 1.1G | 843.78 it/s |
benchmarked in i7-9700, 1TB NVMe SSD
If you are interested to learn more feel free to checkout the note as well!