helmo/github-issues huggingface dataset:
Dataset.from_generator() cost much more time in vscode debugging mode then running mode
State: closed | Author: dontnet-wuenze (NONE)

### Describe the bug

Hey there,
I’m using Dataset.from_generator() to convert a torch_dataset to the Huggingface Dataset.
However, when I debug my code on vscode, I find that it runs really slow on Dataset.from_generator() which may even 20 times longer then run the script on terminal.

### Steps to reproduce the bug

I write a simple test code :

```python
import os
from functools import partial
from typing import Callable

import torch
import time
from torch.utils.data import Dataset as TorchDataset

from datasets import load_from_disk, Dataset as HFDataset
  
import torch  
from torch.utils.data import Dataset  
  
class SimpleDataset(Dataset):  
    def __init__(self, data):  
        self.data = data  
        self.keys = list(data[0].keys())
      
    def __len__(self):  
        return len(self.data)  
      
    def __getitem__(self, index):  
        sample = self.data[index]  
        return {key: sample[key] for key in self.keys}  
  

def TorchDataset2HuggingfaceDataset(torch_dataset: TorchDataset, cache_dir: str = None
) -> HFDataset:
    
    """
        convert torch dataset to huggingface dataset
    """
    generator : Callable[[], TorchDataset] = lambda: (sample for sample in torch_dataset)   

    return HFDataset.from_generator(generator, cache_dir=cache_dir)

if __name__ == '__main__':
    data = [  
        {'id': 1, 'name': 'Alice'},  
        {'id': 2, 'name': 'Bob'},  
        {'id': 3, 'name': 'Charlie'}  
    ]
    
    torch_dataset = SimpleDataset(data)
    start_time = time.time() 
    huggingface_dataset = TorchDataset2HuggingfaceDataset(torch_dataset)
    end_time = time.time()
    print("time: ", end_time - start_time)
    print(huggingface_dataset)
```

### Expected behavior

this test on my machine report that the running time on terminal is 0.086,
however the running time in debugging mode on vscode is 0.25, which I think is much longer than expected.

I’d like to know is the anything wrong in the code or just because of debugging?
I have traced the code and I find is this func which I get stuck.

```python
def create_config_id(
        self,
        config_kwargs: dict,
        custom_features: Optional[Features] = None,
    ) -> str:
...
# stuck in this line
suffix = Hasher.hash(config_kwargs_to_add_to_suffix)
```



### Environment info

- `datasets` version: 2.12.0
- Platform: Linux-5.11.0-27-generic-x86_64-with-glibc2.31
- Python version: 3.11.3
- Huggingface_hub version: 0.17.2
- PyArrow version: 11.0.0
- Pandas version: 2.0.1

Comments: Answered on the forum: https://discuss.huggingface.co/t/dataset-from-generator-cost-much-more-time-in-vscode-debugging-mode-then-running-mode/56005/2
exif_transpose not done to Image (PIL problem)
State: closed | Author: rhajou (NONE)
Labels: name: enhancement

### Feature request

I noticed that some of my images loaded using PIL have some metadata related to exif that can rotate them when loading.
Since the dataset.features.Image uses PIL for loading, the loaded image may be rotated (width and height will be inverted) thus for tasks as object detection and layoutLM this can create some inconsistencies (between input bboxes and input images). 

For now there is no option in datasets.features.Image to specify that. We need to do the following when preparing examples (when preparing images for training, test or inference): 
```
from PIL import Image, ImageOps 
pil = ImageOps.exif_transpose(pil)
```

reference: https://stackoverflow.com/a/63950647/5720150 

Is it possible to add this by default to the datasets.feature.Image ? or to add the option to do the ImageOps.exif_transpose?

Thank you

### Motivation

Prevent having inverted data related to exif metadata that may affect object detection tasks

### Your contribution

Changing in datasets.featrues.Image I can help with that. 

Comments: Indeed, it makes sense to do this by default. 

In the meantime, you can use `.with_transform` to transpose the images when accessing them:

```python
import PIL.ImageOps

def exif_transpose_transform(batch):
  batch["image"] = [PIL.ImageOps.exif_transpose(image) for image in batch["image"]]
  return batch

dataset = dataset.with_transform(exif_transpose_transform)
```

This operation sets some `Image` attributes to `None` (`.format`, `.filename`, etc.), causing our tests to fail, so I think we should wait for Datasets 3.0 to make this change. In version 3.0, storing image paths will be replaced by embedding image bytes, so there will be fewer instances where we use the `.filename` attribute.
Data alteration when loading dataset with unspecified inner sequence length
State: closed | Author: qgallouedec (MEMBER)

### Describe the bug

When a dataset saved with a specified inner sequence length is loaded without specifying that length, the original data is altered and becomes inconsistent.

### Steps to reproduce the bug

```python
from datasets import Dataset, Features, Value, Sequence, load_dataset

# Repository ID
repo_id = "my_repo_id"

# Define features with a specific length of 3 for each inner sequence
specified_features = Features({"key": Sequence(Sequence(Value("float32"), length=3))})

# Create a dataset with the specified features
data = [
    [[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]],
    [[7.0, 8.0, 9.0], [10.0, 11.0, 12.0]],
]
dataset = Dataset.from_dict({"key": data}, features=specified_features)

# Push the dataset to the hub
dataset.push_to_hub(repo_id)

# Define features without specifying the length
unspecified_features = Features({"key": Sequence(Sequence(Value("float32")))})

# Load the dataset from the hub with this new feature definition
dataset = load_dataset(f"qgallouedec/{repo_id}", split="train", features=unspecified_features)

# The obtained data is altered
print(dataset.to_dict())  # {'key': [[[1.0], [2.0]], [[3.0], [4.0]]]}
```


### Expected behavior

```python
print(dataset.to_dict())  # {'key': [[[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]], [[7.0, 8.0, 9.0], [10.0, 11.0, 12.0]]]}
```

### Environment info

- `datasets` version: 2.14.4
- Platform: Linux-6.2.0-32-generic-x86_64-with-glibc2.35
- Python version: 3.9.12
- Huggingface_hub version: 0.15.1
- PyArrow version: 12.0.1
- Pandas version: 2.0.3

Comments: While this issue may seem specific, it led to a silent problem in my workflow that took days to diagnose. If this feature is not intended to be supported, an error should be raised when encountering this configuration to prevent such issues.

Thanks for reporting! This is a MRE:

```python
import pyarrow as pa
from datasets.table import cast_array_to_feature
from datasets import Sequence, Value
data = [
    [[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]],
    [[7.0, 8.0, 9.0], [10.0, 11.0, 12.0]],
]
arr = pa.array(data, pa.list_(pa.list_(pa.float32(), 3)))
cast_array_to_feature(arr, Sequence(Sequence(Value("float32"))))
```

I've opened a PR with a fix.
Dataloader stuck on multiple GPUs
State: closed | Author: kuri54 (NONE)

### Describe the bug

I am trying to get CLIP to fine-tuning with my code.
When I tried to run it on multiple GPUs using accelerate, I encountered the following phenomenon.

- Validation dataloader stuck in 2nd epoch only on multi-GPU
Specifically, when the "for inputs in valid_loader:" process is finished, it does not proceed to the next step. train_loader process is completed. Also, both train and valid are working correctly in the first epoch.
The accelerate command at that time is as follows.
`accelerate launch --multi_gpu --num_processes=2 {script_name.py} {--arg1} {--arg2} ...`

- This will not happen when single GPU is used.
`CUDA_VISIBLE_DEVICES="0" accelerate launch {script_name.py} --arg1 --arg2 ...`
- Setting num_workers=0 in dataloader did not change the result.

### Steps to reproduce the bug

1. The codes for fine-tuning the regular CLIP were updated for accelerate.
2. Run the code with the accelerate command as `accelerate launch --multi_gpu --num_processes=2 {script_name.py} {--arg1} {--arg2} ...` and the above problem will occur.
3. CUDA_VISIBLE_DEVICES="0" accelerate launch {script_name.py} --arg1 --arg2 ...` , it works fine.

### Expected behavior

It Should end normally as if it was run on a single GPU.

### Environment info

Since `datasets-cli env` did not work, the environment is described below.

- OS: Ubuntu 22.04 with Docker
- Docker: 24.0.5, build ced0996
- Python: 3.10.12
- torch==2.0.1
- accelerate==0.21.0
- transformers==4.33.1

Comments: What type of dataset are you using in this script? `torch.utils.data.Dataset` or `datasets.Dataset`? Please share the `datasets` package version if it's the latter. Otherwise, it's better to move this issue to the `accelerate` repo.

Very sorry, I thought I had a repo in `accelerate!`
I will close this issue and repo the issue in the appropriate place.
`dataset.filter` ALWAYS removes the first item from the dataset when using batched=True
State: closed | Author: Taytay (NONE)

### Describe the bug

If you call batched=True when calling `filter`, the first item is _always_ filtered out, regardless of the filter condition.



### Steps to reproduce the bug

Here's a minimal example:
```python
def filter_batch_always_true(batch, indices):
    print("First index being passed into this filter function: ", indices[0])
    return indices  # Keep all indices

data = {"value": list(range(10))}
dataset = Dataset.from_dict(data)

filtered_dataset = dataset.filter(filter_batch_always_true, with_indices=True, batched=True)
print("Length of original dataset: ", len(dataset))
print("Length of filtered_dataset: ", len(filtered_dataset))
print("Is equal to original? ", len(filtered_dataset) == len(dataset))
print("First item of filtered dataset: ", filtered_dataset[0])
print("Last item of filtered dataset: ", filtered_dataset[-1])
```
prints:
```
First index being passed into this filter function:  0
Length of original dataset:  10
Length of filtered_dataset:  9
Is equal to original?  False
First item of filtered dataset:  {'value': 1}
Last item of filtered dataset:  {'value': 9}
```

### Expected behavior

Filter should respect the filter condition.

### Environment info


- `datasets` version: 2.14.4
- Platform: macOS-13.5-arm64-arm-64bit
- Python version: 3.9.18
- Huggingface_hub version: 0.17.1
- PyArrow version: 10.0.1
- Pandas version: 2.0.2


Comments: `filter` treats the function's output as a (selection) mask - `True` keeps the sample, and `False` drops it. In your case, `bool(0)` evaluates to `False`, so dropping the first sample is the correct behavior.

Oh gosh! 🤦  I totally misunderstood the API! My apologies!
Tokenization with multiple workers is too slow
State: closed | Author: macabdul9 (NONE)

I am trying to tokenize a few million documents with multiple workers but the tokenization process is taking forever. 

Code snippet:

```
raw_datasets.map(
            encode_function,
            batched=False,
            num_proc=args.preprocessing_num_workers,
            load_from_cache_file=not args.overwrite_cache,
            remove_columns=[name for name in raw_datasets["train"].column_names if name not in ["input_ids", "labels", "attention_mask"]],
            desc="Tokenizing data",
        )
```

Details:

```
transformers==4.28.0.dev0
datasets==4.28.0.dev0
preprocessing_num_workers==48
```
tokenizer == decapoda-research/llama-7b-hf




Comments: [This](https://huggingface.co/docs/datasets/nlp_process#map) is the most performant way to tokenize a dataset (`batched=True, num_proc=None, return_tensors="np"`) 

If`tokenizer.is_fast` returns `True`, `num_proc` must be `None/1` to benefit from the fast tokenizers' parallelism (the fast tokenizers are implemented in Rust, and Rust multi-threading doesn't work well with Python multi-processing)
Support buffer shuffle for to_tf_dataset
State: open | Author: EthanRock (NONE)
Labels: name: enhancement

### Feature request

I'm using to_tf_dataset to convert a large dataset to tf.data.Dataset and use Keras fit to train model. 
Currently, to_tf_dataset only supports full size shuffle, which can be very slow on large dataset. 
tf.data.Dataset support buffer shuffle by default. 
shuffle(
    buffer_size, seed=None, reshuffle_each_iteration=None, name=None
)

### Motivation

I'm very frustrated to find the loading with shuffling large dataset is very slow. It seems impossible to shuffle before training Keras with big dataset. 

### Your contribution

NA

Comments: cc @Rocketknight1 

Hey! You can implement this yourself, just:

1) Create the dataset with `to_tf_dataset()` with `shuffle=False`
2) Add an `unbatch()` at the end (or use batch_size=1)
3) Add a `shuffle()` to the resulting dataset with your desired buffer size
4) Add a `batch()` at the end again to re-batch your dataset.

Note that the way we construct datasets in `to_tf_dataset()`, we don't actually shuffle the entire dataset in-memory, using `tf.data.Dataset.shuffle()`! Instead, we shuffle an index array and then load from the dataset with that. This means that shuffling with `tf.data.Dataset.shuffle()` will probably be slower and use more memory than our approach - I don't think adding the option for smaller shuffle buffers will actually save you memory on this!

Thanks for your reply! @Rocketknight1 
"We don't actually shuffle the entire dataset in-memory, using tf.data.Dataset.shuffle()! Instead, we shuffle an index array and then load from the dataset with that."
In such case, there will be random access to dataset data during shuffling. When the dataset is large, the performance can be X10 times slow. I have tried many ways with to_tf_dataset() trying to achieve comparable performance with tf.data.Dataset().shuffle(buffer_size).batch(). But the performance with to_tf_dataset() is still slow.
Support multiprocessing for download/extract nestedly
State: open | Author: hgt312 (NONE)
Labels: name: enhancement

### Feature request

Current multiprocessing for download/extract is not done nestedly. For example, when processing SlimPajama, there is only 3 processes (for train/test/val), while there are many files inside these 3 folders

```
Downloading data files #0:   0%|          | 0/1 [00:00<?, ?obj/s]
Downloading data files #1:   0%|          | 0/1 [00:00<?, ?obj/s]
Downloading data files #2:   0%|          | 0/1 [00:00<?, ?obj/s]

Extracting data files #0:   0%|          | 0/1 [00:00<?, ?obj/s]
Extracting data files #1:   0%|          | 0/1 [00:00<?, ?obj/s][A
Extracting data files #2:   0%|          | 0/1 [00:00<?, ?obj/s][A[A
```

### Motivation

speedup dataset loading

### Your contribution

I can help test the feature
Overwrite legacy default config name in `dataset_infos.json` in packaged datasets
State: open | Author: polinaeterna (CONTRIBUTOR)

Currently if we push data as default config with `.push_to_hub` to a repo that has a legacy `dataset_infos.json` file containing a legacy default config name like `{username}--{dataset_name}`, new key `"default"` is added to `dataset_infos.json` along with the legacy one. I think the legacy one should be dropped in this case.

Also, in `load.py` I suggest to check if a legacy config name is indeed a legacy config name because after this fix it might not be the case (this check was first introduced in https://github.com/huggingface/datasets/pull/6218)

Comments: The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/datasets/pr_6231). All of your documentation changes will be reflected on that endpoint.

realized that this pr is still not merged, @lhoestq maybe you can take a look at it? 

I think https://github.com/huggingface/datasets/pull/6218 fixed the issue (a bit differently though)

ah actually nope, let me check

@lhoestq yeah the pr you're referencing doesn't fix the problem when two semantically analogous configs occur in datasets_info.json, i suggest to rewrite the legacy one if it exists during .push_to_hub

Only the old versions of `datasets` use the JSON file over the README and they can only load one config so the name doesn't really matter.

That's why I chose to load the info from the JSON no matter the name (no check to see if it's "username--dataset_name") in my previous PR.

I think you can remove the old info without even checking the name. In this case maybe no need to update load.py 

(also minor: not checking the name makes it more robust to dataset renaming)

@lhoestq okay makes sense... so you think it's not a problem that in some cases we might end up with `dataset_infos.json` having two keys in it?

> @lhoestq okay makes sense... so you think it's not a problem that in some cases we might end up with dataset_infos.json having two keys in it?

Ideally they should have only one config no ? Since old versions of `datasets` simply load the first config in the JSON.
We can overwrite it with the new default one (and no matter the name of the outdated config in the JSON)
Conversion from RGB to BGR in Object Detection tutorial
State: closed | Author: samokhinv (NONE)

The [tutorial](https://huggingface.co/docs/datasets/main/en/object_detection) mentions the necessity of conversion the input image from BGR to RGB

> albumentations expects the image to be in BGR format, not RGB, so you’ll have to convert the image before applying the transform.

[Link to tutorial](https://github.com/huggingface/datasets/blob/0a068dbf3b446417ffd89d32857608394ec699e6/docs/source/object_detection.mdx#L77)

However, relevant albumentations' tutorials [on channels conversion](https://albumentations.ai/docs/examples/example/#read-the-image-from-the-disk-and-convert-it-from-the-bgr-color-space-to-the-rgb-color-space) and  [on boxes](https://albumentations.ai/docs/examples/example_bboxes/) imply that it's not really true no more.

I suggest removing this outdated conversion from the tutorial.

Comments: Good catch!
Support saving datasets with custom formatting
State: open | Author: mariosasko (COLLABORATOR)

Requested in https://discuss.huggingface.co/t/using-set-transform-on-a-dataset-leads-to-an-exception/53036.

I am not sure if supporting this is the best idea for the following reasons:

>For this to work, we would have to pickle a custom transform, which means the transform and the objects it references need to be serializable. Also, deserializing these bytes would make `load_from_disk` unsafe, so I'm not sure this is a good idea. 

@lhoestq WDYT?


Comments: Not a fan of pickling this sort of stuff either.
Note that users can also share the code in their dataset documentation.
`Dataset.to_dict()` ignore `decode=True` with Image feature
State: open | Author: qgallouedec (MEMBER)

### Describe the bug

`Dataset.to_dict` seems to ignore the decoding instruction passed in features.

### Steps to reproduce the bug

```python
import datasets
import numpy as np
from PIL import Image

img = np.random.randint(0, 256, (5, 5, 3), dtype=np.uint8)
img = Image.fromarray(img)

features = datasets.Features({"image": datasets.Image(decode=True)})
dataset = datasets.Dataset.from_dict({"image": [img]}, features=features)
print({key: dataset[key] for key in dataset.column_names})
# {'image': [<PIL.PngImagePlugin.PngImageFile image mode=RGB size=5x5 at 0x7EFBC80E15B0>]}
print(dataset.to_dict())
# {'image': [{'bytes': b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00\x05\x00\x00\x00\x05\x08\x02\x00\x00\x00\x02\r\xb1\xb2\x00\x00\x00[IDATx\x9c\x01P\x00\xaf\xff\x01\x13\x1b<7\xe7\xe0\xdc^6\xed\x04\xc7M\xd2\x9f\x00X\x1b\xb0?\x1ba\x15\xc5 o\xd0\x80\xbe\x19/\x01\xec\x95\x1f\x9f\xffj\xfa1\xa7\xc4X\xea\xbe\xa4g\x00\xc4\x15\xdeC\xc7 \xbbaqe\xc8\xb9\xa9q\xe7\x00,?M\xc0)\xdaD`}\xb1\xdci\x1e\xafC\xa9]%.@\xa6\xf0\xb3\x00\x00\x00\x00IEND\xaeB`\x82', 'path': None}]}
```




### Expected behavior

I would expect `{key: dataset[key] for key in dataset.column_names}` and `dataset.to_dict()` to be equivalent. If the previous behavior is expected, then it should be stated [in the doc](https://huggingface.co/docs/datasets/v2.14.4/en/package_reference/main_classes#datasets.Dataset.to_dict).

### Environment info

- `datasets` version: 2.14.4
- Platform: Linux-6.2.0-31-generic-x86_64-with-glibc2.35
- Python version: 3.9.12
- Huggingface_hub version: 0.15.1
- PyArrow version: 12.0.1
- Pandas version: 2.0.3
- Pillow 9.5.0
- numpy 1.25.2

Comments: We need to implement the `Image` type as a PyArrow extension type (to allow us to override the Python conversion) for this to work as expected. For now, it's best to use your approach indeed.
Unpin fsspec < 2023.9.0
State: closed | Author: albertvillanova (MEMBER)
Labels: name: enhancement

Once root issue is fixed, remove temporary pin of fsspec < 2023.9.0 introduced by:
- #6210

Related to issue:
- #6209

After investigation, I think the root issue is related to the new glob behavior with double asterisk `**` they have introduced in:
- https://github.com/fsspec/filesystem_spec/pull/1329
No-script datasets with ZIP files do not load
State: closed | Author: albertvillanova (MEMBER)
Labels: name: bug

While investigating an issue on a Hub dataset, I have discovered the no-script datasets containing ZIP files do not load.

For example, that no-script dataset containing ZIP files, raises NonMatchingSplitsSizesError:
```python
In [2]: ds = load_dataset("sidovic/LearningQ-qg")

NonMatchingSplitsSizesError: [
  {
    'expected': SplitInfo(name='train', num_bytes=0, num_examples=188660, shard_lengths=None, dataset_name=None), 
    'recorded': SplitInfo(name='train', num_bytes=0, num_examples=0, shard_lengths=None, dataset_name='learning_q-qg')
  }, {
    'expected': SplitInfo(name='validation', num_bytes=0, num_examples=20630, shard_lengths=None, dataset_name=None), 
    'recorded': SplitInfo(name='validation', num_bytes=0, num_examples=0, shard_lengths=None, dataset_name='learning_q-qg')
  }, {
    'expected': SplitInfo(name='test', num_bytes=0, num_examples=18227, shard_lengths=None, dataset_name=None), 
    'recorded': SplitInfo(name='test', num_bytes=0, num_examples=0, shard_lengths=None, dataset_name='learning_q-qg')
  }
]
```

As another example, a no-script dataset containing just a (CSV)-ZIP file, raises a DatasetGenerationError:
```
>               num_examples, num_bytes = writer.finalize()

src/datasets/builder.py:1949: 

>           raise SchemaInferenceError("Please pass `features` or at least one example when writing data")
E           datasets.arrow_writer.SchemaInferenceError: Please pass `features` or at least one example when writing data

src/datasets/arrow_writer.py:598: SchemaInferenceError

The above exception was the direct cause of the following exception:

src/datasets/load.py:2143: in load_dataset
    builder_instance.download_and_prepare(
src/datasets/builder.py:954: in download_and_prepare
    self._download_and_prepare(
src/datasets/builder.py:1049: in _download_and_prepare
    self._prepare_split(split_generator, **prepare_split_kwargs)
src/datasets/builder.py:1813: in _prepare_split
    for job_id, done, content in self._prepare_split_single(

>           raise DatasetGenerationError("An error occurred while generating the dataset") from e
E           datasets.builder.DatasetGenerationError: An error occurred while generating the dataset

src/datasets/builder.py:1958: DatasetGenerationError
```

After investigating, I think this bug was introduced in this PR:
- #5972

Related to:
- https://huggingface.co/datasets/sidovic/LearningQ-qg/discussions/1

CC: @lhoestq