Revert "[Python] Optimize BigQuery copy jobs in file loads using multi-source copy" by shunping · Pull Request #39106 · apache/beam

shunping · 2026-06-25T15:11:31Z

Reverting #38983 since it is causing some postcommit test failure.

…i-source copy (apache#38983)" This reverts commit 8e4ea73.

shunping · 2026-06-25T18:14:56Z

gemini-code-assist · 2026-06-25T18:15:14Z

Summary of Changes

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This pull request serves as a corrective measure to address stability issues in post-commit tests caused by the recent implementation of BigQuery copy job batching. By reverting the batching logic and refactoring the copy job trigger mechanism, the changes aim to restore the reliability of BigQuery file load operations while maintaining correct write disposition behavior.

Highlights

Reversion of PR [Python] Optimize BigQuery copy jobs in file loads using multi-source copy #38983: This pull request reverts the changes introduced in [Python] Optimize BigQuery copy jobs in file loads using multi-source copy #38983 due to post-commit test failures identified in the Apache Beam project.
BigQuery Copy Job Logic: The implementation of BigQuery copy jobs has been simplified by removing the batching logic that previously grouped multiple source tables into a single copy job, reverting to a one-to-one mapping.
Write Disposition Handling: Introduced a new method _determine_write_disposition to explicitly manage write dispositions, ensuring that only the first copy job uses the user-specified disposition while subsequent jobs default to WRITE_APPEND.

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Code Review

This pull request refactors the BigQuery file loads pipeline in the Python SDK to trigger copy jobs individually rather than chunking them into batches. It removes the batching logic and simplifies the copy job configuration. The review feedback highlights three important issues: first, grouping temporary tables by tableId instead of their full hashable destination can cause key collisions across different datasets or projects; second, instantiating BigQueryWrapper inline on every element is inefficient and should be replaced with the existing reusable instance; and third, removing the guard check before appending partitions could lead to empty partitions being created.

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gemini-code-assist · 2026-06-25T18:16:10Z

+          finished_temp_tables_load_job_ids_pc | beam.MapTuple(
              lambda destination, job_reference: (
-                  bigquery_tools.get_hashable_destination(destination),
+                  bigquery_tools.parse_table_reference(destination).tableId,
                  (destination, job_reference)))
          | beam.GroupByKey()
-          | beam.MapTuple(lambda dest, batch: list(batch)))
+          | beam.MapTuple(lambda tableId, batch: list(batch)))


Using only tableId as the grouping key can cause collisions if the pipeline writes to multiple datasets or projects that contain tables with the same name (e.g., dataset_A.my_table and dataset_B.my_table). Using get_hashable_destination ensures that the full destination (project, dataset, and table) is used as the key, preventing incorrect grouping and potential data corruption.

Suggested change

finished_temp_tables_load_job_ids_pc | beam.MapTuple(

lambda destination, job_reference: (

bigquery_tools.get_hashable_destination(destination),

bigquery_tools.parse_table_reference(destination).tableId,

(destination, job_reference)))

| beam.GroupByKey()

| beam.MapTuple(lambda dest, batch: list(batch)))

| beam.MapTuple(lambda tableId, batch: list(batch)))

finished_temp_tables_load_job_ids_pc | beam.MapTuple(

lambda destination, job_reference: (

bigquery_tools.get_hashable_destination(destination),

(destination, job_reference)))

| beam.GroupByKey()

| beam.MapTuple(lambda dest, batch: list(batch)))

gemini-code-assist · 2026-06-25T18:16:10Z

          try:
            schema = bigquery_tools.table_schema_to_dict(
-                self.bq_wrapper.get_table(
+                bigquery_tools.BigQueryWrapper().get_table(


Instantiating BigQueryWrapper inline on every element/iteration inside process is inefficient because it initializes HTTP clients and credentials repeatedly. It is better to reuse the existing self.bq_wrapper instance.

Suggested change

bigquery_tools.BigQueryWrapper().get_table(

self.bq_wrapper.get_table(

gemini-code-assist · 2026-06-25T18:16:10Z

      else:
-        if latest_partition.files:
-          partitions.append(latest_partition.files)
+        partitions.append(latest_partition.files)


Without checking if latest_partition.files is non-empty, an empty list could be appended to partitions if the first file cannot be accepted. Adding a guard prevents empty partitions from being created.

if latest_partition.files: partitions.append(latest_partition.files)

github-actions · 2026-06-25T18:16:17Z

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control. If you'd like to restart, comment assign set of reviewers

Amar3tto · 2026-06-25T18:36:08Z

Waiting for checks

shunping · 2026-06-25T20:49:30Z

All tests passed.

…i-source copy" (apache#39106) * Revert "[Python] Optimize BigQuery copy jobs in file loads using multi-source copy (apache#38983)" This reverts commit 8e4ea73. * Trigger postcommit test.

shunping added 2 commits June 25, 2026 11:10

Revert "[Python] Optimize BigQuery copy jobs in file loads using mult…

387c006

…i-source copy (apache#38983)" This reverts commit 8e4ea73.

Trigger postcommit test.

c470ea0

github-actions Bot added python io gcp labels Jun 25, 2026

shunping mentioned this pull request Jun 25, 2026

The PostCommit Python job is flaky #30513

Open

shunping requested a review from stankiewicz June 25, 2026 18:13

shunping marked this pull request as ready for review June 25, 2026 18:14

shunping requested a review from Amar3tto June 25, 2026 18:15

stankiewicz approved these changes Jun 25, 2026

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gemini-code-assist Bot reviewed Jun 25, 2026

View reviewed changes

shunping changed the title ~~Revert pr 38983~~ Revert "[Python] Optimize BigQuery copy jobs in file loads using multi-source copy" Jun 25, 2026

shunping merged commit eef26ca into apache:master Jun 25, 2026
118 of 119 checks passed

shunping mentioned this pull request Jun 25, 2026

[release-2.75] Cherry-pick #39100 and #39106 to the branch #39117

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Revert "[Python] Optimize BigQuery copy jobs in file loads using multi-source copy"#39106

Revert "[Python] Optimize BigQuery copy jobs in file loads using multi-source copy"#39106
shunping merged 2 commits into
apache:masterfrom
shunping:revert-pr-38983

shunping commented Jun 25, 2026 •

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	bigquery_tools.BigQueryWrapper().get_table(
	self.bq_wrapper.get_table(

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