def _partition_and_combine_block(
block: Block[T], boundaries: List[KeyType], key: KeyFn,
aggs: Tuple[AggregateFn]) -> List[Union[Block, BlockMetadata]]:
"""Partition the block and combine rows with the same key."""
stats = BlockExecStats.builder()
if key is None:
partitions = [block]
else:
partitions = BlockAccessor.for_block(block).sort_and_partition(
boundaries,
[(key, "ascending")] if isinstance(key, str) else key,
descending=False,
)
parts = [BlockAccessor.for_block(p).combine(key, aggs) for p in partitions]
meta = BlockAccessor.for_block(block).get_metadata(
input_files=None, exec_stats=stats.build())
return parts + [meta]
def remote_read(i: int, task: ReadTask,
stats_actor) -> MaybeBlockPartition:
DatasetContext._set_current(context)
stats = BlockExecStats.builder()
# Execute the read task.
block = task()
if context.block_splitting_enabled:
metadata = task.get_metadata()
metadata.exec_stats = stats.build()
else:
metadata = BlockAccessor.for_block(block).get_metadata(
input_files=task.get_metadata().input_files,
exec_stats=stats.build())
stats_actor.record_task.remote(stats_uuid, i, metadata)
return block
def _map_block_nosplit(
block: Block,
block_fn: BlockTransform,
input_files: List[str],
fn: Optional[UDF],
*fn_args,
**fn_kwargs,
) -> Tuple[Block, BlockMetadata]:
stats = BlockExecStats.builder()
builder = DelegatingBlockBuilder()
if fn is not None:
fn_args = (fn, ) + fn_args
for new_block in block_fn(block, *fn_args, **fn_kwargs):
builder.add_block(new_block)
new_block = builder.build()
accessor = BlockAccessor.for_block(new_block)
return new_block, accessor.get_metadata(input_files=input_files,
exec_stats=stats.build())
def map(
idx: int,
block: Block,
output_num_blocks: int,
block_udf: Optional[Callable[[Block], Iterable[Block]]],
random_shuffle: bool,
random_seed: Optional[int],
) -> List[Union[BlockMetadata, Block]]:
stats = BlockExecStats.builder()
if block_udf:
# TODO(ekl) note that this effectively disables block splitting.
blocks = list(block_udf(block))
if len(blocks) > 1:
builder = BlockAccessor.for_block(blocks[0]).builder()
for b in blocks:
builder.add_block(b)
block = builder.build()
else:
block = blocks[0]
block = BlockAccessor.for_block(block)
# Randomize the distribution of records to blocks.
if random_shuffle:
seed_i = random_seed + idx if random_seed is not None else None
block = block.random_shuffle(seed_i)
block = BlockAccessor.for_block(block)
slice_sz = max(1, math.ceil(block.num_rows() / output_num_blocks))
slices = []
for i in range(output_num_blocks):
slices.append(
block.slice(i * slice_sz, (i + 1) * slice_sz, copy=True))
# Randomize the distribution order of the blocks (this prevents empty
# outputs when input blocks are very small).
if random_shuffle:
random = np.random.RandomState(seed_i)
random.shuffle(slices)
num_rows = sum(BlockAccessor.for_block(s).num_rows() for s in slices)
assert num_rows == block.num_rows(), (num_rows, block.num_rows())
metadata = block.get_metadata(input_files=None,
exec_stats=stats.build())
return [metadata] + slices
def from_items(items: List[Any], *, parallelism: int = 200) -> Dataset[Any]:
"""Create a dataset from a list of local Python objects.
Examples:
>>> import ray
>>> ray.data.from_items([1, 2, 3, 4, 5]) # doctest: +SKIP
Args:
items: List of local Python objects.
parallelism: The amount of parallelism to use for the dataset.
Parallelism may be limited by the number of items.
Returns:
Dataset holding the items.
"""
block_size = max(1, len(items) // parallelism)
blocks: List[ObjectRef[Block]] = []
metadata: List[BlockMetadata] = []
i = 0
while i < len(items):
stats = BlockExecStats.builder()
builder = DelegatingBlockBuilder()
for item in items[i : i + block_size]:
builder.add(item)
block = builder.build()
blocks.append(ray.put(block))
metadata.append(
BlockAccessor.for_block(block).get_metadata(
input_files=None, exec_stats=stats.build()
)
)
i += block_size
return Dataset(
ExecutionPlan(
BlockList(blocks, metadata),
DatasetStats(stages={"from_items": metadata}, parent=None),
),
0,
False,
)
def reduce(random_shuffle: bool, random_seed: Optional[int],
*mapper_outputs: List[Block]) -> (Block, BlockMetadata):
stats = BlockExecStats.builder()
builder = DelegatingBlockBuilder()
for block in mapper_outputs:
builder.add_block(block)
new_block = builder.build()
accessor = BlockAccessor.for_block(new_block)
if random_shuffle:
new_block = accessor.random_shuffle(
random_seed if random_seed is not None else None)
accessor = BlockAccessor.for_block(new_block)
new_metadata = BlockMetadata(
num_rows=accessor.num_rows(),
size_bytes=accessor.size_bytes(),
schema=accessor.schema(),
input_files=None,
exec_stats=stats.build(),
)
return new_block, new_metadata
def _execute_read_task(
i: int,
task: ReadTask,
context: DatasetContext,
stats_uuid: str,
stats_actor: ray.actor.ActorHandle,
) -> Tuple[MaybeBlockPartition, BlockPartitionMetadata]:
DatasetContext._set_current(context)
stats = BlockExecStats.builder()
# Execute the task.
block = task()
metadata = task.get_metadata()
if context.block_splitting_enabled:
metadata.exec_stats = stats.build()
else:
metadata = BlockAccessor.for_block(block).get_metadata(
input_files=metadata.input_files, exec_stats=stats.build())
stats_actor.record_task.remote(stats_uuid, i, metadata)
return block, metadata
def _merge(
reduce_fn,
*all_mapper_outputs: List[List[Block]],
reduce_args: Optional[List[Any]] = None,
) -> List[Union[BlockMetadata, Block]]:
"""
Returns list of [BlockMetadata, O1, O2, O3, ...output_num_blocks].
"""
assert (
len({len(mapper_outputs) for mapper_outputs in all_mapper_outputs}) == 1
), "Received different number of map inputs"
stats = BlockExecStats.builder()
merged_outputs = []
if not reduce_args:
reduce_args = []
for mapper_outputs in zip(*all_mapper_outputs):
block, meta = reduce_fn(*reduce_args, *mapper_outputs)
merged_outputs.append(block)
meta = BlockAccessor.for_block(block).get_metadata(
input_files=None, exec_stats=stats.build()
)
return [meta] + merged_outputs
def _merge(
reduce_fn,
*all_mapper_outputs: List[List[Block]],
reduce_args: Optional[List[Any]] = None,
) -> List[Union[BlockMetadata, Block]]:
"""
Returns list of [BlockMetadata, O1, O2, O3, ...output_num_blocks].
"""
assert (len({
len(mapper_outputs)
for mapper_outputs in all_mapper_outputs
}) == 1), "Received different number of map inputs"
stats = BlockExecStats.builder()
if not reduce_args:
reduce_args = []
num_rows = 0
size_bytes = 0
schema = None
for i, mapper_outputs in enumerate(zip(*all_mapper_outputs)):
block, meta = reduce_fn(*reduce_args,
*mapper_outputs,
partial_reduce=True)
yield block
block = BlockAccessor.for_block(block)
num_rows += block.num_rows()
size_bytes += block.size_bytes()
schema = block.schema()
del block
yield BlockMetadata(
num_rows=num_rows,
size_bytes=size_bytes,
schema=schema,
input_files=None,
exec_stats=stats.build(),
)
def aggregate_combined_blocks(
blocks: List[Block[ArrowRow]],
key: KeyFn,
aggs: Tuple[AggregateFn],
finalize: bool,
) -> Tuple[Block[ArrowRow], BlockMetadata]:
"""Aggregate sorted, partially combined blocks with the same key range.
This assumes blocks are already sorted by key in ascending order,
so we can do merge sort to get all the rows with the same key.
Args:
blocks: A list of partially combined and sorted blocks.
key: The column name of key or None for global aggregation.
aggs: The aggregations to do.
finalize: Whether to finalize the aggregation. This is used as an
optimization for cases where we repeatedly combine partially
aggregated groups.
Returns:
A block of [k, v_1, ..., v_n] columns and its metadata where k is
the groupby key and v_i is the corresponding aggregation result for
the ith given aggregation.
If key is None then the k column is omitted.
"""
stats = BlockExecStats.builder()
key_fn = (
(lambda r: r[r._row.schema.names[0]]) if key is not None else (lambda r: 0)
)
iter = heapq.merge(
*[ArrowBlockAccessor(block).iter_rows() for block in blocks], key=key_fn
)
next_row = None
builder = ArrowBlockBuilder()
while True:
try:
if next_row is None:
next_row = next(iter)
next_key = key_fn(next_row)
next_key_name = (
next_row._row.schema.names[0] if key is not None else None
)
def gen():
nonlocal iter
nonlocal next_row
while key_fn(next_row) == next_key:
yield next_row
try:
next_row = next(iter)
except StopIteration:
next_row = None
break
# Merge.
first = True
accumulators = [None] * len(aggs)
resolved_agg_names = [None] * len(aggs)
for r in gen():
if first:
count = collections.defaultdict(int)
for i in range(len(aggs)):
name = aggs[i].name
# Check for conflicts with existing aggregation
# name.
if count[name] > 0:
name = ArrowBlockAccessor._munge_conflict(
name, count[name]
)
count[name] += 1
resolved_agg_names[i] = name
accumulators[i] = r[name]
first = False
else:
for i in range(len(aggs)):
accumulators[i] = aggs[i].merge(
accumulators[i], r[resolved_agg_names[i]]
)
# Build the row.
row = {}
if key is not None:
row[next_key_name] = next_key
for agg, agg_name, accumulator in zip(
aggs, resolved_agg_names, accumulators
):
if finalize:
row[agg_name] = agg.finalize(accumulator)
else:
row[agg_name] = accumulator
builder.add(row)
except StopIteration:
break
ret = builder.build()
return ret, ArrowBlockAccessor(ret).get_metadata(None, exec_stats=stats.build())
def _get_metadata(
table: Union["pyarrow.Table", "pandas.DataFrame"]) -> BlockMetadata:
stats = BlockExecStats.builder()
return BlockAccessor.for_block(table).get_metadata(
input_files=None, exec_stats=stats.build())
def do_zip(block1: Block, block2: Block) -> (Block, BlockMetadata):
stats = BlockExecStats.builder()
b1 = BlockAccessor.for_block(block1)
result = b1.zip(block2)
br = BlockAccessor.for_block(result)
return result, br.get_metadata(input_files=[], exec_stats=stats.build())
def _ndarray_to_block(ndarray: np.ndarray) -> Block[np.ndarray]:
stats = BlockExecStats.builder()
block = BlockAccessor.batch_to_block(ndarray)
metadata = BlockAccessor.for_block(block).get_metadata(
input_files=None, exec_stats=stats.build())
return block, metadata
def aggregate_combined_blocks(
blocks: List[Block[Tuple[KeyType, AggType]]],
key: KeyFn,
aggs: Tuple[AggregateFn],
) -> Tuple[Block[Tuple[KeyType, U]], BlockMetadata]:
"""Aggregate sorted, partially combined blocks with the same key range.
This assumes blocks are already sorted by key in ascending order,
so we can do merge sort to get all the rows with the same key.
Args:
blocks: A list of partially combined and sorted blocks.
key: The key function that returns the key from the row
or None for global aggregation.
aggs: The aggregations to do.
Returns:
A block of (k, v_1, ..., v_n) tuples and its metadata where k is
the groupby key and v_i is the corresponding aggregation result for
the ith given aggregation.
If key is None then the k element of tuple is omitted.
"""
stats = BlockExecStats.builder()
key_fn = (lambda r: r[0]) if key else (lambda r: 0)
iter = heapq.merge(
*[SimpleBlockAccessor(block).iter_rows() for block in blocks], key=key_fn
)
next_row = None
ret = []
while True:
try:
if next_row is None:
next_row = next(iter)
next_key = key_fn(next_row)
def gen():
nonlocal iter
nonlocal next_row
while key_fn(next_row) == next_key:
yield next_row
try:
next_row = next(iter)
except StopIteration:
next_row = None
break
first = True
accumulators = [None] * len(aggs)
for r in gen():
if first:
for i in range(len(aggs)):
accumulators[i] = r[i + 1] if key else r[i]
first = False
else:
for i in range(len(aggs)):
accumulators[i] = aggs[i].merge(
accumulators[i], r[i + 1] if key else r[i]
)
if key is None:
ret.append(
tuple(
agg.finalize(accumulator)
for agg, accumulator in zip(aggs, accumulators)
)
)
else:
ret.append(
(next_key,)
+ tuple(
agg.finalize(accumulator)
for agg, accumulator in zip(aggs, accumulators)
)
)
except StopIteration:
break
return ret, SimpleBlockAccessor(ret).get_metadata(
None, exec_stats=stats.build()
)
def _get_metadata(table: "pyarrow.Table") -> BlockMetadata:
stats = BlockExecStats.builder()
return BlockAccessor.for_block(table).get_metadata(
input_files=None, exec_stats=stats.build())
def _df_to_block(df: "pandas.DataFrame") -> Block[ArrowRow]:
stats = BlockExecStats.builder()
import pyarrow as pa
block = pa.table(df)
return (block, BlockAccessor.for_block(block).get_metadata(
input_files=None, exec_stats=stats.build()))
