apache/beam

DirectRunner unnecessarily re-scheules tasks after exceptions

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#18,141 opened on Jun 3, 2022

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Description

Seems like DirectRunner keeps scheduling tasks when exceptions occur when reading BigQuery results (and possibly in other cases).

I verified that rescheduling is not coming from BigQuery. AFAIKT a _MonitorTask that gets added at following location does not get removed properly when an exception is thrown. https://github.com/apache/beam/blob/master/sdks/python/apache_beam/runners/direct/executor.py#L361

To reproduce: (1) Raise a 'ValueError' at the beginning of method BigQueryWrapper.convert_row_to_dict at following location. https://github.com/apache/beam/blob/master/sdks/python/apache_beam/io/bigquery.py#L1061 (2) Setup Python SDK and run bigquery_tornadoes with DirectRunner. python -m apache_beam.examples.cookbook.bigquery_tornadoes --output <table> --project <project>

Imported from Jira BEAM-1462. Original Jira may contain additional context. Reported by: chamikara.

Contributor guide

Research direction
Examine the MonitorTask lifecycle in executor.py, focusing on how tasks are added and removed when exceptions occur. Trace the code path from BigQueryWrapper.convert row to dict to understand why the task is not cleaned up.
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python
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backend
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