Release 6.5.11 hotfix 20260623

[ChenNingjie1218]

What problem does this PR solve?

Issue Number: ref #10337

Problem Summary:

Backport the exchange sender memory usage limit from #10387 to the v6.5.11 hotfix baseline for HF-1041.

This PR is opened only to trigger upstream GitHub CI for the hotfix and should not be merged.

What is changed and how it works?

• Add max_buffered_bytes_in_executor and propagate it to DAG/MPP response writers.
• Flush buffered rows by byte threshold to limit exchange sender memory usage.
• Add/adapt unit tests for streaming and MPP exchange writers.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

[ti-chi-bot]

This cherry pick PR is for a release branch and has not yet been approved by triage owners.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-chi-bot]

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[coderabbitai]

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[ti-chi-bot]

Hi @ChenNingjie1218. Thanks for your PR.

I'm waiting for a pingcap member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

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Welcome @ChenNingjie1218!

It looks like this is your first PR to pingcap/tiflash 🎉.

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[kumailf]

/retest-required

[ti-chi-bot]

@kumailf: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

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In response to this:

/retest-required

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[iamxy]

/ok-to-test

[pingcap-cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ windtalker
❌ ningjie.chen

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[ChenNingjie1218]

/retest

[kumailf]

/test pull-integration-test

[kumailf]

/test pull-integration-test

[ChenNingjie1218]

/retest-required

[ChenNingjie1218]

/test pull-integration-test

[ChenNingjie1218]

/test pull-unit-test

[ChenNingjie1218]

/test pull-unit-test