Fix block size for transfer

mars/oscar/__init__.py

@@ -39,6 +39,7 @@
 )
 from .backends import allocate_strategy
 from .backends.pool import MainActorPoolType
+from .backends.transfer import temp_transfer_block_size
 from .batch import extensible
 from .core import (
     ActorRef,

mars/oscar/backends/transfer.py

@@ -40,6 +40,21 @@
 DEFAULT_TRANSFER_BLOCK_SIZE = 4 * 1024**2
 
 
+@contextlib.contextmanager
+def temp_transfer_block_size(size: int):
+    global DEFAULT_TRANSFER_BLOCK_SIZE
+
+    if size == DEFAULT_TRANSFER_BLOCK_SIZE:
+        yield
+    else:
+        default_size = DEFAULT_TRANSFER_BLOCK_SIZE
+        DEFAULT_TRANSFER_BLOCK_SIZE = size
+        try:
+            yield
+        finally:
+            DEFAULT_TRANSFER_BLOCK_SIZE = default_size
+
+
 def _get_buffer_size(buf) -> int:
     try:
         return buf.nbytes

mars/services/storage/transfer.py

@@ -207,10 +207,11 @@ async def send_batch_data(
                         rest_keys.append(data_key)
 
                 if local_buffers:
-                    # for data that supports buffer protocol on both sides
-                    # hand over to oscar to transfer data
-                    await mo.copyto_via_buffers(local_buffers, remote_buffer_refs)
-                    await receiver_ref.close_writers(session_id, copied_keys)
+                    with mo.temp_transfer_block_size(block_size):
+                        # for data that supports buffer protocol on both sides
+                        # hand over to oscar to transfer data
+                        await mo.copyto_via_buffers(local_buffers, remote_buffer_refs)
+                        await receiver_ref.close_writers(session_id, copied_keys)
             else:
                 rest_keys = to_send_keys
                 rest_readers = readers