[chenBright]

What problem does this PR solve?

Issue Number: resolve

Problem Summary:

Histogram window tests can fail under high CI load because fixed sleeps and short polling timeouts
do not guarantee that the background sampler has completed the required sampling rounds

What is changed and the side effects?

Changed:

• Replace the fixed sleep with polling that first confirms the sample enters the window, then waits for it to expire.
• Allow 30 seconds per polling phase in both histogram window tests, checking every 100 ms.
• Verify that expired bucket counts and sums are zero while the underlying histogram retains its cumulative values.

Side effects:

• Performance effects:

• Breaking backward compatibility:

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Check List:

• Please make sure your changes are compilable.
• When providing us with a new feature, it is best to add related tests.
• Please follow Contributor Covenant Code of Conduct.

[Copilot]

🔵 Needs a closer look

Polling transient histogram values remains unreliable when sampler updates are missed.

0 open findings

What changed in this PR

This PR improves histogram window test reliability by replacing fixed waits with polling and expiration checks.

Changes:

• Polls for asynchronous sampler updates.
• Extends retry windows.
• Validates expired histogram values.

File	Summary
test/​bvar_histogram_unittest.cpp	Updates histogram window timing and expiration assertions; polling can still miss transient results.

🧠 Review effort: Lite

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[wwbmmm]

[replied by brpc-oncall robot] Test-only change: replacing the fixed sleeps with sampler-aware polling is the right direction and the new expiration assertions look correct, but the first polling phase of window_forgets_old_samples still depends on catching a transient window value, which can be missed on a busy host.

[Copilot]

🟡 Changes recommended

The test does not prove that the window observed a non-zero sample before expiration.

1 open issue

• Verify non-zero window sample before expiration · New

_{Review effort: Lite}

[Copilot]

Warning

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Copilot review overview

3 open issues

• The comment says “100 ms per retry” but this hunk doesn’t show any sleep/backoff in the retry loop;… · New
• std::make_unique requires C++14; if this repo/tests are compiled as C++11 (common for older… · New
• This test now directly assigns to h._sampler, which tightly couples it to bvar::Histogram… · New

1 resolved since last review

• Verify non-zero window sample before expiration

_{Review effort: Lite}

[chenBright]

@wwbmmm The first two Copilot comments are false positives, and the third is an optional maintainability suggestion. No required fixes remain. This PR is ready to merge

[chenBright]

@wwbmmm PTAL.