[KafkaIO] Extract expiring memoizing supplier as a separate utility and run end offset refreshes in the current thread

[sjvanrossum]

Partially revert changes to KafkaLatestOffsetEstimator, refreshing end offsets on a background thread is complicated to maintain. This is part of a series of PRs to simplify the poll loop in ReadFromKafkaDoFn.

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Summary of Changes

Hello @sjvanrossum, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refactors the Kafka offset estimation logic by extracting a generic expiring memoizing supplier. This change simplifies the ReadFromKafkaDoFn by removing the need for a custom background thread for offset refreshes, improving maintainability and contributing to a cleaner poll loop.

Highlights

• New Utility Class: Introduced ExpiringMemoizingSerializableSupplier, a thread-safe, serializable supplier that caches its result for a specified duration, with lightweight locking for concurrency.
• Kafka Offset Estimation Refactoring: Replaced the custom background thread-based offset refresh mechanism in KafkaLatestOffsetEstimator within ReadFromKafkaDoFn with the newly extracted ExpiringMemoizingSerializableSupplier.
• Simplification and Maintainability: This change simplifies the KafkaLatestOffsetEstimator by removing complex background thread management, contributing to the broader goal of simplifying the Kafka poll loop in ReadFromKafkaDoFn.

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[sjvanrossum]

Note for reviewers, I'm aware of Guava's Suppliers.memoizeWithExpiration(...). Guava's expiry mechanism refreshes by locking and having all observers wait on the newly supplied value. The expiry mechanism extracted from KafkaLatestOffsetEstimator refreshes by claiming the expiration timestamp's low bit and returning the current value to other observers until the claim holding observer's newly supplied value is made visible by progressing the expiration timestamp by one period with the claim bit unset.

[github-actions]

Checks are failing. Will not request review until checks are succeeding. If you'd like to override that behavior, comment assign set of reviewers

[sjvanrossum]

Run Java PreCommit

[sjvanrossum]

Note for reviewers, I'm aware of Guava's Suppliers.memoizeWithExpiration(...). Guava's expiry mechanism refreshes by locking and having all observers wait on the newly supplied value. The expiry mechanism extracted from KafkaLatestOffsetEstimator refreshes by claiming the expiration timestamp's low bit and returning the current value to other observers until the claim holding observer's newly supplied value is made visible by progressing the expiration timestamp by one period with the claim bit unset.

Renaming the class to WeakExpiringMemoizingSerializableSupplier (FashionablyLateExpiringMemoizingSerializableSupplier?) might help to convey that difference.

[sjvanrossum]

Run Java_Amazon-Web-Services2_IO_Direct PreCommit

[sjvanrossum]

Run Java_GCP_IO_Direct PreCommit

[sjvanrossum]

Partially revert changes to KafkaLatestOffsetEstimator, refreshing end offsets on a background thread is complicated to maintain. This is part of a series of PRs to simplify the poll loop in ReadFromKafkaDoFn.

---

Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

• Mention the appropriate issue in your description (for example: addresses #123), if applicable. This will automatically add a link to the pull request in the issue. If you would like the issue to automatically close on merging the pull request, comment fixes #<ISSUE NUMBER> instead.
• Update CHANGES.md with noteworthy changes.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

See the Contributor Guide for more tips on how to make review process smoother.

To check the build health, please visit https://github.com/apache/beam/blob/master/.test-infra/BUILD_STATUS.md

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI or the workflows README to see a list of phrases to trigger workflows.

Note for reviewers, the next step for end offset estimation will be to replace the consumer with an admin client (and removing support for all Kafka client versions <2.6.0) and memoize the KafkaFuture<ListOffsetsResult.ListOffsetsResultInfo> returned for the partition result of a list offsets request instead of the final result. This will restore the background thread refresh mechanism, but the executing thread is an IO thread managed by the Kafka client library instead of the single threaded executor used before this change.

The stress tests I run show that replacing the consumer with an admin client reduces memory usage by ~90% (~150MiB for the consumer, ~15MiB for the admin client).

[sjvanrossum]

assign set of reviewers

[sjvanrossum]

Test failure in UnboundedScheduledExecutorServiceTest seems unrelated to this PR.

[github-actions]

Assigning reviewers:

R: @Abacn for label java.
R: @Dippatel98 for label kafka.

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[github-actions]

Reminder, please take a look at this pr: @Abacn @Dippatel98

[github-actions]

Assigning new set of reviewers because Pr has gone too long without review. If you would like to opt out of this review, comment assign to next reviewer:

R: @chamikaramj for label java.
R: @johnjcasey for label kafka.

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[sjvanrossum]

Run Java PreCommit

[sjvanrossum]

Run Java_IOs_Direct PreCommit

[github-actions]

Reminder, please take a look at this pr: @chamikaramj @johnjcasey

[sjvanrossum]

Run Java PreCommit

[sjvanrossum]

@chamikaramj @johnjcasey the AWS SQS and JMS tests keep failing but are unrelated to this change. I keep merging master into this PR branch hoping that it's resolved, but no luck so far.

Would you mind reviewing this PR? I've got a follow up to this that leverages Admin to reduce memory utilization for offset estimation while also bringing back background refreshes based on Admin#listOffsets(Map).

[github-actions]

Assigning new set of reviewers because Pr has gone too long without review. If you would like to opt out of this review, comment assign to next reviewer:

R: @Abacn for label java.
R: @shunping for label kafka.

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[github-actions]

Reminder, please take a look at this pr: @Abacn @shunping

[tvalentyn]

R: @johnjcasey

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[johnjcasey]

Are we packing the state here so that we can use a single atomic set?

[derrickaw]

Hi @damccorm or @jrmccluskey, can you merge this PR at your convenience? Thanks!