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koriweb d8a80f6272 chore(wiki): dangling 링크 canonical 정규화 (768파일/1200건)
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Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-08 12:24:15 +09:00

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wiki-2026-0508-single-source-of-truth Single Source of Truth (SSoT) 10_Wiki/Topics verified self
SSoT
Single Source of Truth
Authoritative Source
none A 0.9 applied
architecture
data
principle
consistency
2026-05-10 pending
language framework
typescript redux

Single Source of Truth (SSoT)

매 한 줄

"매 fact 의 1 authoritative location. Everywhere else 의 derive.". 매 information architecture 의 fundamental principle — duplication 의 minimize 후 매 derived view 의 cache/projection 으로 처리. 매 frontend (Redux), backend (master DB), DevOps (Git as IaC source) 의 cross-cutting pattern.

매 핵심

매 layers

  • DB layer: master DB + read replicas (no parallel sources).
  • App state: Redux store / TanStack Query cache.
  • Config: Git repo (Infrastructure as Code).
  • Identity: SCIM-synced IdP (Okta/Entra).
  • Schema: protobuf / OpenAPI as type-source.

매 derived view

  • Materialized views (DB).
  • Selectors / memoized derive (frontend).
  • Search indexes (Elastic) reflecting master.
  • Reporting cubes built from master.

매 응용

  1. Redux Toolkit createSlice — 1 store, derived UI.
  2. Git → Terraform → Cloud (no console drift).
  3. SCIM provisioning — IdP authoritative.
  4. CDC (Debezium) — master DB → downstream consumers.
  5. Event sourcing — log as SSoT.

💻 패턴

Redux normalize + selector

import { createSlice, createSelector } from '@reduxjs/toolkit';

const usersSlice = createSlice({
  name: 'users',
  initialState: { byId: {} as Record<string, User> },
  reducers: { upsert: (state, { payload }) => { state.byId[payload.id] = payload; } },
});

export const selectUser = (id: string) => (state: RootState) => state.users.byId[id];
export const selectActiveUsers = createSelector(
  (s: RootState) => Object.values(s.users.byId),
  (users) => users.filter(u => u.active),
);

Terraform as IaC SSoT

resource "aws_s3_bucket" "logs" {
  bucket = "company-logs-prod"
  tags = { managed_by = "terraform", repo = "infra" }
}
# Console changes drift-detected via `terraform plan`

Debezium CDC

connector.class: io.debezium.connector.postgresql.PostgresConnector
database.hostname: master.db
table.include.list: public.orders
plugin.name: pgoutput
# Master postgres → Kafka → search/analytics consumers

Schema-first (protobuf)

syntax = "proto3";
message User {
  string id = 1;
  string email = 2;
  bool active = 3;
}
// codegen → TS, Go, Python types — single schema source

Materialized view (Postgres)

CREATE MATERIALIZED VIEW user_stats AS
SELECT user_id, COUNT(*) AS orders, SUM(total) AS revenue
FROM orders GROUP BY user_id;

REFRESH MATERIALIZED VIEW CONCURRENTLY user_stats;

SCIM provisioning

// IdP (Okta) → /scim/v2/Users — app receives, never originates user identity
app.put('/scim/v2/Users/:id', (req, res) => {
  await db.upsertUser(req.params.id, req.body);
  res.status(200).json(req.body);
});

TanStack Query cache as derived

const { data: user } = useQuery({
  queryKey: ['user', id],
  queryFn: () => api.getUser(id),
  staleTime: 60_000,
});
// Server is SSoT — cache is derived view with TTL

매 결정 기준

상황 Approach
Cross-system data sync CDC from master DB
Cloud config Git + Terraform
User identity IdP + SCIM
Frontend state Normalized Redux + selectors
Analytics Reflect master via warehouse

기본값: master + derived projections — never multi-master unless conflict-resolution strategy defined.

🔗 Graph

🤖 LLM 활용

언제: design-time data flow review, drift audit, cache invalidation strategy. 언제 X: distributed systems with offline-first requirement — CRDT 가 적합.

안티패턴

  • Dual-write: 매 app writes both DB and search — drift inevitable. CDC 사용.
  • Console drift: cloud console change without IaC update.
  • Cached as authoritative: TTL stale → cache mistakenly trusted.

🧪 검증 / 중복

  • Verified (Fowler, Kleppmann DDIA, Redux docs, Terraform best practices).
  • 신뢰도 A.

🕓 Changelog

날짜 변경
2026-05-08 Phase 1
2026-05-10 Manual cleanup — SSoT principle, master + derived patterns, CDC/IaC/SCIM