josteece/github-issues huggingface dataset:
Lookahead streaming support?
Opened by PicoCreator (open)

### Feature request

From what I understand, streaming dataset currently pulls the data, and process the data as it is requested.
This can introduce significant latency delays when data is loaded into the training process, needing to wait for each segment.

While the delays might be dataset specific (or even mapping instruction/tokenizer specific)

Is it possible to introduce a `streaming_lookahead` parameter, which is used for predictable workloads (even shuffled dataset with fixed seed). As we can predict in advance what the next few datasamples will be. And fetch them while the current set is being trained.

With enough CPU & bandwidth to keep up with the training process, and a sufficiently large lookahead, this will reduce the various latency involved while waiting for the dataset to be ready between batches.

### Motivation

Faster streaming performance, while training over extra large TB sized datasets

### Your contribution

I currently use HF dataset, with pytorch lightning trainer for RWKV project, and would be able to help test this feature if supported.

Comments:
In which format is your dataset? We could expose the `pre_buffer` flag for Parquet to use PyArrow's background thread pool to speed up loading.
[Docs] The "Process" how-to guide lacks description of `select_columns` function
Opened by unifyh (closed)

### Feature request

The [how to process dataset guide](https://huggingface.co/docs/datasets/main/en/process) currently does not mention the [`select_columns`](https://huggingface.co/docs/datasets/main/en/package_reference/main_classes#datasets.Dataset.select_columns) function. It would be nice to include it in the guide.

### Motivation

This function is a commonly requested feature (see this [forum thread](https://discuss.huggingface.co/t/how-to-create-a-new-dataset-from-another-dataset-and-select-specific-columns-and-the-data-along-with-the-column/15120) and #5468 #5474). However, it has not been included in the guide since its implementation by PR #5480.

Mentioning it in the guide would help future users discover this added feature.

### Your contribution

I could submit a PR to add a brief description of the function to said guide.

Comments:
Great idea, feel free to open a PR! :)
[BUG] Dataset initialized from in-memory data does not create cache.
Opened by MattYoon (closed)

### Describe the bug

`Dataset` initialized from in-memory data (dictionary in my case, haven't tested with other types) does not create cache when processed with the `map` method, unlike `Dataset` initialized by other methods such as `load_dataset`.

### Steps to reproduce the bug

```python
# below code was run the second time so the map function can be loaded from cache if exists

from datasets import load_dataset, Dataset

dataset = load_dataset("tatsu-lab/alpaca")['train']

dataset = dataset.map(lambda x: {'input': x['input'] + 'hi'}) # some random map
print(len(dataset.cache_files))
# 1

# copy the exact same data but initialize from a dictionary
memory_dataset = Dataset.from_dict({
    'instruction': dataset['instruction'],
    'input': dataset['input'],
    'output': dataset['output'],
    'text': dataset['text']})

memory_dataset = memory_dataset.map(lambda x: {'input': x['input'] + 'hi'}) # exact same map
print(len(memory_dataset.cache_files))
# Map: 100%|██████████| 52002[/52002]
# 0
```

### Expected behavior

The `map` function should create cache regardless of the method the `Dataset` was created.

### Environment info

- `datasets` version: 2.14.2
- Platform: Linux-5.15.0-41-generic-x86_64-with-glibc2.31
- Python version: 3.9.16
- Huggingface_hub version: 0.14.1
- PyArrow version: 11.0.0
- Pandas version: 1.5.3

Comments:
This is expected behavior. You must provide `cache_file_name` when performing `.map` on an in-memory dataset for the result to be cached.
load local json_file as dataset
Opened by CiaoHe (closed)

### Describe the bug

I tried to load local json file as dataset but failed to parsing json file because some columns are 'float' type.

### Steps to reproduce the bug

1. load json file with certain columns are 'float' type. For example `data = load_data("json", data_files=JSON_PATH)`
2. Then, the error will be triggered like `ArrowInvalid: Could not convert '-0.2253' with type str: tried to convert to double

### Expected behavior

Should allow some columns are 'float' type, at least it should convert those columns to str type.
I tried to avoid the error by naively convert the float item to str:
```python
# if col type is not str, we need to convert it to str
mapping = {}
for col in keys:
    if isinstance(dataset[0][col], str):
        mapping[col] = [row.get(col) for row in dataset]
    else:
        mapping[col] = [str(row.get(col)) for row in dataset]
```

### Environment info

- `datasets` version: 2.14.2
- Platform: Linux-5.4.0-52-generic-x86_64-with-glibc2.31
- Python version: 3.9.16
- Huggingface_hub version: 0.16.4
- PyArrow version: 12.0.0
- Pandas version: 2.0.1

Comments:
Hi! We use PyArrow to read JSON files, and PyArrow doesn't allow different value types in the same column. #5776 should address this.

In the meantime, you can combine `Dataset.from_generator` with the above code to cast the values to the same type. 

Thanks for your help!
HF Datasets data access is extremely slow even when in memory
Opened by NightMachinery (open)

### Describe the bug

Doing a simple `some_dataset[:10]` can take more than a minute.

Profiling it:
<img width="1280" alt="image" src="https://github.com/huggingface/datasets/assets/36224762/e641fb95-ff02-4072-9016-5416a65f75ab">

`some_dataset` is completely in memory with no disk cache.

This is proving fatal to my usage of HF Datasets. Is there a way I can forgo the arrow format and store the dataset as PyTorch tensors so that `_tensorize` is not needed? And is `_consolidate` supposed to take this long?

It's faster to produce the dataset from scratch than to access it from HF Datasets!

### Steps to reproduce the bug

I have uploaded the dataset that causes this problem [here](https://huggingface.co/datasets/NightMachinery/hf_datasets_bug1).

```python
#!/usr/bin/env python3
import sys
import time
import torch
from datasets import load_dataset


def main(dataset_name):
    # Start the timer
    start_time = time.time()

    # Load the dataset from Hugging Face Hub
    dataset = load_dataset(dataset_name)

    # Set the dataset format as torch
    dataset.set_format(type="torch")

    # Perform an identity map
    dataset = dataset.map(lambda example: example, batched=True, batch_size=20)

    # End the timer
    end_time = time.time()

    # Print the time taken
    print(f"Time taken: {end_time - start_time:.2f} seconds")


if __name__ == "__main__":
    dataset_name = "NightMachinery/hf_datasets_bug1"
    print(f"dataset_name: {dataset_name}")
    main(dataset_name)
```

### Expected behavior

_

### Environment info

- `datasets` version: 2.13.1
- Platform: Linux-5.15.0-76-generic-x86_64-with-glibc2.35
- Python version: 3.10.12
- Huggingface_hub version: 0.16.4
- PyArrow version: 12.0.1
- Pandas version: 2.0.3

Comments:
Possibly related:
- https://github.com/pytorch/pytorch/issues/22462
TypeError when loading from GCP bucket
Opened by bilelomrani1 (closed)

### Describe the bug

Loading a dataset from a GCP bucket raises a type error. This bug was introduced recently (either in 2.14 or 2.14.1), and appeared during a migration from 2.13.1.

### Steps to reproduce the bug

Load any file from a GCP bucket:

```python
import datasets

datasets.load_dataset("json", data_files=["gs://..."])
```

The following exception is raised:

```python
Traceback (most recent call last):
...
packages/datasets/data_files.py", line 335, in resolve_pattern
    protocol_prefix = fs.protocol + "://" if fs.protocol != "file" else ""
TypeError: can only concatenate tuple (not "str") to tuple
```

With a `GoogleFileSystem`, the attribute `fs.protocol` is a tuple `('gs', 'gcs')` and hence cannot be concatenated with a string.


### Expected behavior

The file should be loaded without exception.

### Environment info

- `datasets` version: 2.14.1
- Platform: macOS-13.2.1-x86_64-i386-64bit
- Python version: 3.10.12
- Huggingface_hub version: 0.16.4
- PyArrow version: 12.0.1
- Pandas version: 2.0.3


Comments:
Thanks for reporting, @bilelomrani1.

We are fixing it. 

We have fixed it. We are planning to do a patch release today.
Dataset.get_nearest_examples does not return all feature values for the k most similar datapoints - side effect of Dataset.set_format
Opened by aschoenauer-sebag (closed)

### Describe the bug

Hi team!

I observe that there seems to be a side effect of `Dataset.set_format`: after setting a format and creating a FAISS index, the method `get_nearest_examples` from the `Dataset` class, fails to retrieve anything else but the embeddings themselves - not super useful. This is not the case if not using the `set_format` method: you can also retrieve any other feature value, such as an index/id/etc.

Are you able to reproduce what I observe?

### Steps to reproduce the bug

```python

from datasets import Dataset
import numpy as np

foo = {'vectors': np.random.random((100,1024)), 'ids': [str(u) for u in range(100)]}
foo = Dataset.from_dict(foo)
foo.set_format('numpy', ['vectors'])
foo.add_faiss_index('vectors')
new_vector = np.random.random(1024)
scores, res = foo.get_nearest_examples('vectors', new_vector, k=3)
```
This will return, for the resulting most similar vectors to `new_vector` - in particular it will not return the `ids` feature:
```
{'vectors': array([[random values ...]])}
```

### Expected behavior

The expected behavior happens when the `set_format` method is not called:
```python

from datasets import Dataset
import numpy as np

foo = {'vectors': np.random.random((100,1024)), 'ids': [str(u) for u in range(100)]}
foo = Dataset.from_dict(foo)
# foo.set_format('numpy', ['vectors'])
foo.add_faiss_index('vectors')
new_vector = np.random.random(1024)
scores, res = foo.get_nearest_examples('vectors', new_vector, k=3)
```
This *will*  return the `ids` of the similar vectors - with unfortunately a list of lists in lieu of the array I think for caching reasons - read it elsewhere
```
{'vectors': [[random values on multiple lines...]], 'ids': ['x', 'y', 'z']}
```

### Environment info

- `datasets` version: 2.12.0
- Platform: Linux-5.4.0-155-generic-x86_64-with-glibc2.31
- Python version: 3.10.6
- Huggingface_hub version: 0.15.1
- PyArrow version: 11.0.0
- Pandas version: 1.5.3


Comments:
Actually, my bad -- specifying
```python
foo.set_format('numpy', ['vectors'], output_all_columns=True)
```
fixes it.
FilesIterable skips all the files after a hidden file
Opened by dkrivosic (closed)

### Describe the bug

When initializing `FilesIterable` with a list of file paths using `FilesIterable.from_paths`, it will discard all the files after a hidden file.
The problem is in [this line](https://github.com/huggingface/datasets/blob/88896a7b28610ace95e444b94f9a4bc332cc1ee3/src/datasets/download/download_manager.py#L233C26-L233C26) where `return` should be replaced by `continue`. 

### Steps to reproduce the bug

https://colab.research.google.com/drive/1SQlxs4y_LSo1Q89KnFoYDSyyKEISun_J#scrollTo=93K4_blkW-8-

### Expected behavior

The script should print all the files except the hidden one.

### Environment info

- `datasets` version: 2.14.1
- Platform: Linux-5.15.109+-x86_64-with-glibc2.35
- Python version: 3.10.6
- Huggingface_hub version: 0.16.4
- PyArrow version: 9.0.0
- Pandas version: 1.5.3

Comments:
Thanks for reporting. We've merged a PR with a fix.
Loading local data files initiates web requests
Opened by lytning98 (closed)

As documented in the [official docs](https://huggingface.co/docs/datasets/v2.14.0/en/package_reference/loading_methods#datasets.load_dataset.example-2), I tried to load datasets from local files by
```python
# Load a JSON file
from datasets import load_dataset
ds = load_dataset('json', data_files='path/to/local/my_dataset.json')
```
But this failed on a web request because I'm executing the script on a machine without Internet access. Stacktrace shows
```
in PackagedDatasetModuleFactory.__init__(self, name, data_dir, data_files, download_config, download_mode)
    940 self.download_config = download_config
    941 self.download_mode = download_mode
--> 942 increase_load_count(name, resource_type="dataset")
```
I've read from the source code that this can be fixed by setting environment variable to run in offline mode. I'm just wondering that is this an expected behaviour that even loading a LOCAL JSON file requires Internet access by default? And what's the point of requesting to `increase_load_count` on some server when loading just LOCAL data files?

Comments:
fsspec dependency is set too low
Opened by iXce (closed)

### Describe the bug

fsspec.callbacks.TqdmCallback (used in https://github.com/huggingface/datasets/blob/73bed12ecda17d1573fd3bf73ed5db24d3622f86/src/datasets/utils/file_utils.py#L338) was first released in fsspec [2022.3.0](https://github.com/fsspec/filesystem_spec/releases/tag/2022.3.0, commit where it was added: https://github.com/fsspec/filesystem_spec/commit/9577c8a482eb0a69092913b81580942a68d66a76#diff-906155c7e926a9ff58b9f23369bb513b09b445f5b0f41fa2a84015d0b471c68cR180), however the dependency is set to 2021.11.1 https://github.com/huggingface/datasets/blob/main/setup.py#L129



### Steps to reproduce the bug

1. Install fsspec==2021.11.1
2. Install latest datasets==2.14.1
3. Import datasets, import fails due to lack of `fsspec.callbacks.TqdmCallback`

### Expected behavior

No import issue

### Environment info

N/A

Comments:
Thanks for reporting! A PR with a fix has just been merged.
Support `fsspec` in `Dataset.to_<format>` methods
Opened by mariosasko (closed)

Supporting this should be fairly easy.

Requested on the forum [here](https://discuss.huggingface.co/t/how-can-i-convert-a-loaded-dataset-in-to-a-parquet-file-and-save-it-to-the-s3/48353).

Comments:
Hi @mariosasko unless someone's already working on it, I guess I can tackle it!

Hi! Sure, feel free to tackle this.

#self-assign

I'm assuming this should just cover `to_csv`, `to_parquet`, and `to_json`, right? As `to_list` and `to_dict` just return Python objects, `to_pandas` returns a `pandas.DataFrame` and `to_sql` just inserts into a SQL DB, is that right?

Fixed by #6096.
Changing pixel values of images in the Winoground dataset
Opened by ZitengWangNYU (open)

Hi, as I followed the instructions, with lasted "datasets" version:
"
from datasets import load_dataset
examples = load_dataset('facebook/winoground', use_auth_token=<YOUR USER ACCESS TOKEN>)
"
I got slightly different datasets in colab and in my hpc environment. Specifically, the pixel values of images are slightly different. 
I thought it was due to the package version difference, but today's morning I found out that my winoground dataset in colab became the same with the one in my hpc environment. The dataset in colab can produce the correct result but now it is gone as well. 

Can you help me with this? What causes the datasets to have the wrong pixel values?

Comments:
resume_download with streaming=True
Opened by NicolasMICAUX (closed)

### Describe the bug

I used:
```
dataset = load_dataset(
    "oscar-corpus/OSCAR-2201",
    token=True,
    language="fr",
    streaming=True,
    split="train"
)
```
Unfortunately, the server had a problem during the training process. I saved the step my training stopped at.
But how can I resume download from step 1_000_´000 without re-streaming all the first 1 million docs of the dataset?

`download_config=DownloadConfig(resume_download=True)` seems to not work with streaming=True.

### Steps to reproduce the bug

```
from datasets import load_dataset, DownloadConfig
dataset = load_dataset(
    "oscar-corpus/OSCAR-2201",
    token=True,
    language="fr",
    streaming=True,  # optional
    split="train",
    download_config=DownloadConfig(resume_download=True)
)
# interupt the run and try to relaunch it => this restart from scratch
```

### Expected behavior

I would expect a parameter to start streaming from a given index in the dataset.

### Environment info

- `datasets` version: 2.14.0
- Platform: Linux-5.19.0-45-generic-x86_64-with-glibc2.29
- Python version: 3.8.10
- Huggingface_hub version: 0.15.1
- PyArrow version: 12.0.1
- Pandas version: 2.0.0

Comments:
Currently, it's not possible to efficiently resume streaming after an error. Eventually, we plan to support this for Parquet (see https://github.com/huggingface/datasets/issues/5380). 

Ok thank you for your answer

I'm closing this as a duplicate of #5380
Why is the speed difference of gen example so big?
Opened by pixeli99 (closed)

```python
def _generate_examples(self, metadata_path, images_dir, conditioning_images_dir):
        with open(metadata_path, 'r') as file:
            metadata = json.load(file)

        for idx, item in enumerate(metadata):
            image_path = item.get('image_path')
            text_content = item.get('text_content')
            image_data = open(image_path, "rb").read()
            yield idx, {
                "text": text_content,
                "image": {
                    "path": image_path,
                    "bytes": image_data,
                },
                "conditioning_image": {
                    "path": image_path,
                    "bytes": image_data,
                },
            }
```
Hello, 

I use the above function to deal with my local data set, but I am very surprised that the speed at which I generate example is very different. When I start a training task, **sometimes 1000examples/s, sometimes only 10examples/s.**

![image](https://github.com/huggingface/datasets/assets/46072190/cdc17661-8267-4fd8-b30c-b74d505efd9b)

I'm not saying that speed is changing all the time. I mean, the reading speed is different in different training, which will cause me to start training over and over again until the speed of this generation of examples is normal.


Comments:
Hi!

It's hard to explain this behavior without more information. Can you profile the slower version with the following code
```python
import cProfile, pstats
from datasets import load_dataset

with cProfile.Profile() as profiler:
    ds = load_dataset(...)

stats = pstats.Stats(profiler).sort_stats("cumtime")
stats.print_stats()
```
and share the output?
Fix host URL in The Pile datasets 
Opened by nickovchinnikov (open)

### Describe the bug

In  #3627 and  #5543, you tried to fix the host URL in The Pile datasets. But both URLs are not working now:

`HTTPError: 404 Client Error: Not Found for URL: https://the-eye.eu/public/AI/pile_preliminary_components/PUBMED_title_abstracts_2019_baseline.jsonl.zst`
And
`ConnectTimeout: HTTPSConnectionPool(host='mystic.the-eye.eu', port=443): Max retries exceeded with url: /public/AI/pile_preliminary_components/PUBMED_title_abstracts_2019_baseline.jsonl.zst (Caused by ConnectTimeoutError(, 'Connection to mystic.the-eye.eu timed out. (connect timeout=10.0)'))`

### Steps to reproduce the bug

```
from datasets import load_dataset

# This takes a few minutes to run, so go grab a tea or coffee while you wait :)
data_files = "https://mystic.the-eye.eu/public/AI/pile_preliminary_components/PUBMED_title_abstracts_2019_baseline.jsonl.zst"
pubmed_dataset = load_dataset("json", data_files=data_files, split="train")
pubmed_dataset
```

Result:
`ConnectTimeout: HTTPSConnectionPool(host='mystic.the-eye.eu', port=443): Max retries exceeded with url: /public/AI/pile_preliminary_components/PUBMED_title_abstracts_2019_baseline.jsonl.zst (Caused by ConnectTimeoutError(, 'Connection to mystic.the-eye.eu timed out. (connect timeout=10.0)'))`

And

```
from datasets import load_dataset

# This takes a few minutes to run, so go grab a tea or coffee while you wait :)
data_files = "https://the-eye.eu/public/AI/pile_preliminary_components/PUBMED_title_abstracts_2019_baseline.jsonl.zst"
pubmed_dataset = load_dataset("json", data_files=data_files, split="train")
pubmed_dataset
```

Result:
`HTTPError: 404 Client Error: Not Found for URL: https://the-eye.eu/public/AI/pile_preliminary_components/PUBMED_title_abstracts_2019_baseline.jsonl.zst`

### Expected behavior

Downloading as normal.

### Environment info

Environment info

    `datasets` version: 2.9.0
    Platform: Windows
    Python version: 3.9.13


Comments:
Multi-processed `Dataset.map` slows down a lot when `import torch`
Opened by ShinoharaHare (closed)

### Describe the bug

When using `Dataset.map` with `num_proc > 1`, the speed slows down much if I add `import torch` to the start of the script even though I don't use it.

I'm not sure if it's `torch` only or if any other package that is "large" will also cause the same result.
BTW, `import lightning` also slows it down.

Below are the progress bars of `Dataset.map`, the only difference between them is with or without `import torch`, but the speed varies by 6-7 times.

- without `import torch` ![image](https://github.com/huggingface/datasets/assets/47121592/0233055a-ced4-424a-9f0f-32a2afd802c2)
- with `import torch` ![image](https://github.com/huggingface/datasets/assets/47121592/463eafb7-b81e-4eb9-91ca-fd7fe20f3d59)


### Steps to reproduce the bug

Below is the code I used, but I don't think the dataset and the mapping function have much to do with the phenomenon.

```python3
from datasets import load_from_disk, disable_caching
from transformers import AutoTokenizer
# import torch
# import lightning

def rearrange_datapoints(
    batch,
    tokenizer,
    sequence_length,
):
    datapoints = []
    
    input_ids = []
    for x in batch['input_ids']:
        input_ids += x
        while len(input_ids) >= sequence_length:
            datapoint = input_ids[:sequence_length]
            datapoints.append(datapoint)
            input_ids[:sequence_length] = []

    if input_ids:
        paddings = [-1] * (sequence_length - len(input_ids))
        datapoint = paddings + input_ids if tokenizer.padding_side == 'left' else input_ids + paddings
        datapoints.append(datapoint)
    
    batch['input_ids'] = datapoints
    return batch


if __name__ == '__main__':
    disable_caching()

    tokenizer = AutoTokenizer.from_pretrained('...', use_fast=False)
    dataset = load_from_disk('...')
    
    dataset = dataset.map(
        rearrange_datapoints,
        fn_kwargs=dict(
            tokenizer=tokenizer,
            sequence_length=2048,
        ),
        batched=True,
        num_proc=8,
    )

```

### Expected behavior

The multi-processed `Dataset.map` function speed between with and without `import torch` should be the same.

### Environment info

- `datasets` version: 2.13.1
- Platform: Linux-3.10.0-1127.el7.x86_64-x86_64-with-glibc2.31
- Python version: 3.10.11
- Huggingface_hub version: 0.14.1
- PyArrow version: 12.0.0
- Pandas version: 2.0.1

Comments:
A duplicate of https://github.com/huggingface/datasets/issues/5929