DongHyeonkaandClaude Opus 5
b2963105a8
The keycloak project ended with four open questions that design could not
settle. A two-VM lab was built to answer them by measurement, and this is
that material: 26 experiments, 125 raw command outputs, 22 browser captures.
Follows the import procedure in README.md.
source/ the originating repository verbatim — 78 documents, 28 SVGs,
8 manifests, plus .source-revision recording the commit
final/ the SSOT
document.md 729 lines written from the 29 experiment documents, not
concatenated: what was predicted, what was measured, and
where the measurement itself was wrong
evidence/raw 125 outputs, flattened to <experiment>__<file> because
the originals collided (01-baseline.txt appeared three
times) and the audit only globs the top level
evidence/meta one per raw file; command and exitCode are null and the
README says why rather than inventing them
evidence/browser 22 captures
assets/ three diagrams through techviz
.techviz/ their VizSpecs
A separate project rather than an addition to keycloak: the B-layer answers
that project's four questions, but the A, C and D layers are about cluster
failure, SSO and operations, and one document.md should hold one subject.
The four question records there can point here through 관계.
Recorded rather than papered over: only three of the 28 diagrams were
remade. The repository forbids hand-drawn SVG and forbids titles inside the
canvas; all 28 originals carry both, so converting them is redrawing, not
reformatting. They stay in source/ and the gap is written into the document.
verify-pipeline.py passes. audit-records.py reports no issues.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
52 lines
2.4 KiB
Markdown
52 lines
2.4 KiB
Markdown
---
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kind: CONCEPT
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slug: messaging-kafka-c02
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title: 느린 메시지 하나가 그 파티션의 워터마크를 붙든다
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topic: state-machines-and-ownership
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project: clean-architecture-backend-template
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status: 게시 전
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sourceRevision: 21234e38cdb9a926cbc92bb97a2aee2e4a7d2916
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rootTreeNode: concept:messaging-kafka-c02
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evidenceCapturedOn: 2026-09-01
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assets:
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- key: messaging-kafka-c02
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file: ../../../final/evidence/rendered/messaging-kafka-c02.svg
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- key: messaging-kafka-c02-diagram
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file: ../../../final/assets/diagrams/messaging-kafka-c02.svg
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evidence:
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- ../../../final/evidence/raw/messaging-kafka-c02.txt
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source:
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- 원본 분석 절은 analysis/messaging/messaging-kafka.md#L87 이다.
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module: messaging-kafka
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---
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# 느린 메시지 하나가 그 파티션의 워터마크를 붙든다
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오프셋 커밋은 집합이 아니라 워터마크다. 동시 처리에서 오프셋이 순서 없이 끝나므로 연속 구간만 커밋한다.
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## 본문
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<!-- body:start -->
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오프셋 커밋은 집합이 아니라 워터마크다.
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> "A Kafka offset commit is a watermark, not a set: committing offset 13 declares that everything below it is done. With concurrent handlers, offsets finish out of order — 10 and 12 may complete while 11 is still running — and committing 13 at that moment would silently discard 11."
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## 완료 표시가 커밋으로 가는 갈림
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:::evidence key="messaging-kafka-c02-diagram" alt="완료 표시 맵에서 연속 구간과 빈 자리 뒤 구간으로 화살표가 나가고 빈 자리 뒤 구간만 빗금으로 표시된 구조" caption="완료 표시가 커밋으로 가는 갈림" zoom="false"
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:::
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그 대가도 적혀 있다 — 느린 메시지 하나가 그 파티션의 워터마크를 붙든다. 그것이 옳은 교환이라는 근거는 대안이 메시지를 잃는다는 것이고, 지연은 소비자 랙으로 보인다는 것이다.
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## 이 기록이 다루는 파일 범위
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:::evidence key="messaging-kafka-c02" alt="코드베이스에서 파일 목록을 만든 출력 25줄. 이 기록이 다루는 범위가 그 목록이다." caption="코드베이스 파일 목록 — 25줄 · exit 0" zoom="true"
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:::
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## 워커 없는 오프셋을 되돌리는 경로
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> "A delivered offset with no worker behind it holds the contiguous watermark back forever: nothing will ever complete it, so the partition stops committing while continuing to consume."
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<!-- body:end -->
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