Flaky test: CompactionTaskTest.testCompactionWithTimestampDimension #20430

This issue was generated automatically by Claude Code (Anthropic's AI coding agent) running a scheduled CI-triage routine on behalf of @FrankChen021. Analysis and suggested fixes are AI-produced; please verify before acting on them.

Status: Resolved by #20320
Subject: CompactionTaskTest.testCompactionWithTimestampDimension (embedded-tests, unit tests (25, C*))
Failures: 1 · First seen: 2026-09-10 · Last seen: 2026-09-10

Root cause

CompactionTestBase.verifySegmentsCount waits for a single Broker segment/metadataCache/sync/time event and then asserts against sys.segments once. The Overlord already reported 2 segments, but the Broker query returned nothing because the observed sync predates the compaction result.

Suggested fix

#20320 (merged 2026-09-30) polls sys.segments in verifyNumVisibleSegmentsIs until it matches, with a bounded timeout.

Occurrences

Failed push-triggered master jobs only. The daily triage routine adds one row per new failed job.