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from __future__ import annotations
import pyarrow
from distributed.protocol.serialize import dask_deserialize, dask_serialize
if pyarrow.__version__ < "0.10":
raise ImportError(
"Need pyarrow >= 0.10 . "
"See https://arrow.apache.org/docs/python/install.html"
)
@dask_serialize.register(pyarrow.RecordBatch)
def serialize_batch(batch):
sink = pyarrow.BufferOutputStream()
writer = pyarrow.RecordBatchStreamWriter(sink, batch.schema)
writer.write_batch(batch)
writer.close()
buf = sink.getvalue()
header = {}
frames = [buf]
return header, frames
@dask_deserialize.register(pyarrow.RecordBatch)
def deserialize_batch(header, frames):
blob = frames[0]
reader = pyarrow.RecordBatchStreamReader(pyarrow.BufferReader(blob))
return reader.read_next_batch()
@dask_serialize.register(pyarrow.Table)
def serialize_table(tbl):
sink = pyarrow.BufferOutputStream()
writer = pyarrow.RecordBatchStreamWriter(sink, tbl.schema)
writer.write_table(tbl)
writer.close()
buf = sink.getvalue()
header = {}
frames = [buf]
return header, frames
@dask_deserialize.register(pyarrow.Table)
def deserialize_table(header, frames):
blob = frames[0]
reader = pyarrow.RecordBatchStreamReader(pyarrow.BufferReader(blob))
return reader.read_all()
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