Remove ProcessPool subclass

src/datasets/arrow_dataset.py

@@ -58,6 +58,7 @@
 import pyarrow as pa
 import pyarrow.compute as pc
 from huggingface_hub import HfApi, HfFolder
+from multiprocess import Pool
 from requests import HTTPError
 
 from . import config
@@ -112,7 +113,7 @@
 from .utils.hub import hf_hub_url
 from .utils.info_utils import is_small_dataset
 from .utils.metadata import DatasetMetadata
-from .utils.py_utils import Literal, ProcessPool, asdict, convert_file_size_to_int, iflatmap_unordered, unique_values
+from .utils.py_utils import Literal, asdict, convert_file_size_to_int, iflatmap_unordered, unique_values
 from .utils.stratify import stratified_shuffle_split_generate_indices
 from .utils.tf_utils import dataset_to_tf, minimal_tf_collate_fn, multiprocess_dataset_to_tf
 from .utils.typing import ListLike, PathLike
@@ -1504,7 +1505,7 @@ def save_to_disk(
         shard_lengths = [None] * num_shards
         shard_sizes = [None] * num_shards
         if num_proc > 1:
-            with ProcessPool(num_proc) as pool:
+            with Pool(num_proc) as pool:
                 with pbar:
                     for job_id, done, content in iflatmap_unordered(
                         pool, Dataset._save_to_disk_single, kwargs_iterable=kwargs_per_job
@@ -3166,7 +3167,7 @@ def format_new_fingerprint(new_fingerprint: str, rank: int) -> str:
                     logger.info(
                         f"Reprocessing {len(kwargs_per_job)}/{num_shards} shards because some of them were missing from the cache."
                     )
-                with ProcessPool(len(kwargs_per_job)) as pool:
+                with Pool(len(kwargs_per_job)) as pool:
                     os.environ = prev_env
                     logger.info(f"Spawning {num_proc} processes")
                     with logging.tqdm(

src/datasets/builder.py

@@ -33,6 +33,7 @@
 
 import fsspec
 import pyarrow as pa
+from multiprocess import Pool
 from tqdm.contrib.concurrent import thread_map
 
 from . import config, utils
@@ -68,7 +69,6 @@
 from .utils.filelock import FileLock
 from .utils.info_utils import VerificationMode, get_size_checksum_dict, verify_checksums, verify_splits
 from .utils.py_utils import (
-    ProcessPool,
     classproperty,
     convert_file_size_to_int,
     has_sufficient_disk_space,
@@ -1543,7 +1543,7 @@ def _prepare_split(
             shards_per_job = [None] * num_jobs
             shard_lengths_per_job = [None] * num_jobs
 
-            with ProcessPool(num_proc) as pool:
+            with Pool(num_proc) as pool:
                 with pbar:
                     for job_id, done, content in iflatmap_unordered(
                         pool, self._prepare_split_single, kwargs_iterable=kwargs_per_job
@@ -1802,7 +1802,7 @@ def _prepare_split(
             shards_per_job = [None] * num_jobs
             shard_lengths_per_job = [None] * num_jobs
 
-            with ProcessPool(num_proc) as pool:
+            with Pool(num_proc) as pool:
                 with pbar:
                     for job_id, done, content in iflatmap_unordered(
                         pool, self._prepare_split_single, kwargs_iterable=kwargs_per_job

src/datasets/utils/py_utils.py

@@ -1330,33 +1330,9 @@ def _write_generator_to_queue(queue: queue.Queue, func: Callable[..., Iterable[Y
     return i
 
 
-class ProcessPool(multiprocess.pool.Pool):
-    """
-    A multiprocess.pool.Pool implementation that keeps track of child process' PIDs,
-    and can detect if a child process has been restarted.
-    """
-
-    def __init__(self, *args, **kwargs) -> None:
-        super().__init__(*args, **kwargs)
-        self._last_pool_pids = self._get_current_pool_pids()
-        self._has_restarted_subprocess = False
-
-    def _get_current_pool_pids(self) -> Set[int]:
-        return {f.pid for f in self._pool}
-
-    def has_restarted_subprocess(self) -> bool:
-        if self._has_restarted_subprocess:
-            # If the pool ever restarted a subprocess,
-            # we don't check the PIDs again.
-            return True
-        current_pids = self._get_current_pool_pids()
-        self._has_restarted_subprocess = current_pids != self._last_pool_pids
-        self._last_pool_pids = current_pids
-        return self._has_restarted_subprocess
-
 
 def iflatmap_unordered(
-    pool: ProcessPool,
+    pool: Union[multiprocessing.pool.Pool, multiprocess.pool.Pool],
     func: Callable[..., Iterable[Y]],
     *,
     kwargs_iterable: Iterable[dict],

tests/test_arrow_dataset.py

@@ -1352,9 +1352,9 @@ def test_map_caching(self, in_memory):
             with self._caplog.at_level(WARNING):
                 with self._create_dummy_dataset(in_memory, tmp_dir) as dset:
                     with patch(
-                        "datasets.arrow_dataset.ProcessPool",
+                        "datasets.arrow_dataset.Pool",
                         new_callable=PickableMagicMock,
-                        side_effect=datasets.arrow_dataset.ProcessPool,
+                        side_effect=datasets.arrow_dataset.Pool,
                     ) as mock_pool:
                         with dset.map(lambda x: {"foo": "bar"}, num_proc=2) as dset_test1:
                             dset_test1_data_files = list(dset_test1.cache_files)