Revert "[Dataflow Streaming] Prevent commit threads from sharing commit streams"

[arunpandianp]

Reverts #37847

The change is causing StreamingEngineWorkCommitter to create a new WindmillStreamPool per commit.

[gemini-code-assist]

Summary of Changes

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This pull request reverts a recent change (#37847) that introduced an unintended regression in the Dataflow Streaming worker. The original change, intended to isolate commit threads, inadvertently caused the StreamingEngineWorkCommitter to create a new WindmillStreamPool for every commit, leading to inefficient resource utilization. This revert restores the previous behavior, ensuring correct WindmillStreamPool instantiation and resolving the observed performance issue.

Highlights

• Revert of Stream Pool Isolation: Undid a previous change that aimed to isolate commit threads by using a separate WindmillStreamPool for each committer.
• WindmillStreamPool Configuration Restored: Restored the WindmillStreamPool creation to utilize numCommitThreads instead of a fixed value of 1.
• Regression Fix: Addressed a regression where the previous change caused StreamingEngineWorkCommitter to incorrectly create a new WindmillStreamPool per commit.

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Changelog

• runners/google-cloud-dataflow-java/worker/src/main/java/org/apache/beam/runners/dataflow/worker/StreamingDataflowWorker.java
  • Reverted the modification to WindmillStreamPool creation, changing the stream pool size from '1' back to 'numCommitThreads'.

Activity

• Initiated as a direct revert of pull request [Dataflow Streaming] Prevent commit threads from sharing commit streams #37847.
• Identified a regression where the previous change led to StreamingEngineWorkCommitter creating a new WindmillStreamPool per commit.
• Provided a visual aid (screenshot) to demonstrate the impact of the regression.

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[arunpandianp]

R: @scwhittle

[github-actions]

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

[chamikaramj]

LGTM. Thanks.

[chamikaramj]

I can merge when tests pass.