googleapis · tswast · Oct 6, 2025 · Oct 3, 2025
@@ -15,6 +15,7 @@
 from __future__ import annotations

 import math
+import os
 import threading
 from typing import Literal, Mapping, Optional, Sequence, Tuple
 import warnings
@@ -58,7 +59,7 @@
 MAX_SUBTREE_FACTORINGS = 5
 _MAX_CLUSTER_COLUMNS = 4
 MAX_SMALL_RESULT_BYTES = 10 * 1024 * 1024 * 1024  # 10G
-
+_MAX_READ_STREAMS = os.cpu_count()

 SourceIdMapping = Mapping[str, str]

@@ -323,7 +324,10 @@ def _export_gbq(
            self.bqclient.update_table(table, ["schema"])

        return executor.ExecuteResult(
-            row_iter.to_arrow_iterable(),
+            row_iter.to_arrow_iterable(
+                bqstorage_client=self.bqstoragereadclient,
+                max_stream_count=_MAX_READ_STREAMS,
+            ),
            array_value.schema,
            query_job,
            total_bytes_processed=row_iter.total_bytes_processed,
@@ -668,7 +672,8 @@ def _execute_plan_gbq(

        return executor.ExecuteResult(
            _arrow_batches=iterator.to_arrow_iterable(
-                bqstorage_client=self.bqstoragereadclient
+                bqstorage_client=self.bqstoragereadclient,
+                max_stream_count=_MAX_READ_STREAMS,
            ),
            schema=og_schema,
            query_job=query_job,