Tao Liao created BEAM-11916:
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Summary: Combine failed on large PCollection of uint64 arrays
Key: BEAM-11916
URL: https://issues.apache.org/jira/browse/BEAM-11916
Project: Beam
Issue Type: Bug
Components: sdk-go
Affects Versions: 2.28.0
Environment: Google Dataflow
Reporter: Tao Liao
We came across an issue with the Combine operation with Apache Beam Go SDK
(v2.28.0), when running a pipeline on Google Cloud Dataflow. Source code:
https://github.com/le0000000/dataflow_combine
We understand that the Go SDK is experimental but it would be great if someone
can help us understand if there’s anything wrong with our code, or if there's a
bug in the Go SDK or Dataflow. The issue only happens when running the pipeline
with Google Dataflow, with some large data set. We are trying to combine a
_PCollection<pairedVec>_, with
_type pairedVec struct {_
_Vec1 [1048576]uint64_
_Vec2 [1048576]uint64_
_}_
There are 10,000,000 items in the PCollection. After reading the input file,
Dataflow scheduled 1000 workers to generate the PCollection, and started to do
the combination. Then the worker number reduced to almost 1 and lasted for a
very long time. Eventually the job failed with the following error log:
2021-03-02T06:13:40.438112597ZWorkflow failed. Causes:
S09:CombinePerKey/CoGBK'1/Read+CombinePerKey/main.combineVecFn+CombinePerKey/main.combineVecFn/Extract+beam.dropKeyFn+main.flattenVecFn+textio.Write/beam.addFixedKeyFn+textio.Write/CoGBK/Write
failed., The job failed because a work item has failed 4 times. Look in
previous log entries for the cause of each one of the 4 failures. For more
information, see https://cloud.google.com/dataflow/docs/guides/common-errors.
The work item was attempted on these workers:
go-job-1-1614659244459204-03012027-u5s6-harness-q8tx Root cause: The worker
lost contact with the service.,
go-job-1-1614659244459204-03012027-u5s6-harness-44hk Root cause: The worker
lost contact with the service.,
go-job-1-1614659244459204-03012027-u5s6-harness-05nm Root cause: The worker
lost contact with the service.,
go-job-1-1614659244459204-03012027-u5s6-harness-l22w Root cause: The worker
lost contact with the service.
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