eventservice: advance scan window for pending syncpoints

[asddongmen]

What problem does this PR solve?

Issue Number: close #5546

This PR splits the eventBroker runtime fix from #5542.

When the event service scan window is pinned by another lagging dispatcher, a dispatcher with a pending syncpoint barrier can get an empty scan range and fail to advance far enough to emit the syncpoint. The existing local scan-window advance path handled pending DDL barriers only.

What is changed and how it works?

• Detect pending syncpoint events before the uncapped scan end ts.
• Reuse the local scan-window advance path when either a DDL or syncpoint barrier is pending.
• Ensure the local range crosses nextSyncPointTs when the syncpoint would otherwise remain outside the bounded step.
• Add focused unit coverage for the pending syncpoint case.

Source PR: #5542

Check List

Tests

• Unit test

Commands run:

• git diff --check
• PATH=/usr/local/go/bin:$PATH GOTOOLCHAIN=auto go test ./pkg/eventservice -run TestGetScanTaskDataRangeEmptyAfterCappingWithPendingSyncPointCrossesSyncPoint -count=1
• PATH=/usr/local/go/bin:$PATH GOTOOLCHAIN=auto make unit_test_pkg PKG=./pkg/eventservice/...

Questions

Will it cause performance regression or break compatibility?

No. The change only expands an existing local scan-window advance path to cover pending syncpoint barriers, matching the DDL barrier behavior.

Do you need to update user documentation, design documentation or monitoring documentation?

No.

Release note

None

Summary by CodeRabbit

• Bug Fixes
  • Improved scan-range handling so pending barrier events are respected when advancing work windows.
  • Prevented scan advancement from skipping over sync-point barriers, helping preserve correct event ordering.
  • Updated logging to reflect pending barrier events more accurately.
• Tests
  • Added coverage for scan-range behavior when a pending sync-point crosses the current scan window.

[ti-chi-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: e23bbef0-9812-4c13-89b6-48895285475e

📥 Commits

Reviewing files that changed from the base of the PR and between d220ee9 and db2ad80.

📒 Files selected for processing (2)

• pkg/eventservice/event_broker.go
• pkg/eventservice/event_broker_test.go

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📝 Walkthrough

Walkthrough

Modifies getScanTaskDataRange in the event broker to detect pending sync-point barrier events alongside pending DDL events, and to locally advance the scan window—capping it just past the next sync-point timestamp when needed. Adds a unit test validating this capping behavior.

Changes

Sync point scan window fix

Layer / File(s)	Summary
Detect and handle pending sync-point in scan window advance pkg/eventservice/event_broker.go	Reads dispatcher's next sync-point timestamp, computes pending sync-point flag within current scan window, combines with pending DDL to trigger local advance of CommitTsEnd, caps advance just past nextSyncPointTs, and updates logging to report both pending DDL and sync-point state.
Test coverage for sync-point crossing pkg/eventservice/event_broker_test.go	Adds a test enabling sync points that asserts getScanTaskDataRange returns needScan=true with CommitTsEnd equal to nextSyncPointTs + 1.

Estimated code review effort: 2 (Simple) | ~15 minutes

Suggested labels: lgtm, approved

Suggested reviewers: lidezhu, hongyunyan

Poem

A rabbit watched the scan window creep,
stuck while sync points lay asleep 💤
Now barriers nudge the range ahead,
past the sync point, forward instead.
Hop, hop, progress — no more stall,
tests confirm it, one and all! 🐇

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: advancing the eventservice scan window for pending syncpoints.
Description check	✅ Passed	The description includes the issue number, change summary, tests, questions, and release note as required by the template.
Linked Issues check	✅ Passed	The changes match #5546 by detecting pending syncpoints, advancing the scan range locally, crossing nextSyncPointTs, and adding unit coverage.
Out of Scope Changes check	✅ Passed	The PR stays within scope, touching only the eventBroker scan-window logic and a focused unit test for the syncpoint case.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.12.2)

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[gemini-code-assist]

Code Review

This pull request introduces support for advancing the scan window when there are pending sync point events, ensuring dispatchers can make forward progress and cross sync points even when the global scan window is pinned. A unit test has been added to verify this behavior. Feedback is provided regarding a potential race condition or inconsistency caused by loading task.nextSyncPoint twice, with a suggestion to reuse the already loaded value.

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[asddongmen]

/test all

[asddongmen]

/test all

[wk989898]

What will happen if localScanMaxTs Ts is less than nextSyncPointTs?

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lidezhu

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [lidezhu]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-07-01 18:14:52.466787652 +0000 UTC m=+236034.167167065: ☑️ agreed by lidezhu.