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ADR-0092: Orphan-Blob Garbage Collection With a Quarantine Bin
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Architecture
Architecture
1. Introduction and Goals
2. Architecture Constraints
3. Context and Scope
4. Solution Strategy
5. Building Block View
6. Runtime View
7. Deployment View
8. Crosscutting Concepts
9. Architecture Decisions
10. Quality Requirements
11. Risks and Technical Debt
12. Glossary
The arrival bundle format
Decisions (ADRs)
Decisions (ADRs)
ADR-0001: Content-Addressed Document Storage with PostgreSQL as Source of Truth
ADR-0002: Single Instance with Scope Hierarchy and Copy-on-Derive
ADR-0003: Fixed Life Cycle States with Configurable Review Processes
ADR-0004: Global Catalogs for Roles and Document Types with Per-Scope Activation
ADR-0005: Modular Monolith
ADR-0006: Three-Layer Search with In-Database Index and Pluggable LLM
ADR-0007: Angular Frontend with Server-Side-Only Enforcement
ADR-0008: Flyway Migrations and jOOQ Codegen from the Migrated Schema
ADR-0009: RLS Enforcement via a Session-Scoped Authorized Scope Set
ADR-0010: Self-Managed QMS via an Internal Mandator
ADR-0011: Authentication via OIDC SSO with Server-Side (BFF) Sessions
ADR-0012: Permission-Based Authorization and System Bootstrap
ADR-0013: User Identity Lifecycle
ADR-0014: Electronic Signatures (Part 11 / Annex 11-Capable)
ADR-0015: Document Effectivity, Periodic Review & Validity
ADR-0016: Data Retention, Disposal & Privacy (FADP / GDPR)
ADR-0017: Multi-Part Version Content
ADR-0018: Non-Functional Targets (Capacity, Availability, Security)
ADR-0019: Notifications & Tasks
ADR-0020: Internationalization (Content Language, Time Zones, Formatting)
ADR-0021: General Typed Document Relationships
ADR-0022: Read-Acknowledgement & Questionnaires
ADR-0023: Migration / Import — Current Released State
ADR-0024: Draft / In-Review Cancellation
ADR-0025: Disposal & Erasure Mechanics (Storage, Index, Backups)
ADR-0026: RLS Runtime Safety — Connection-Pool Scope Isolation
ADR-0027: RLS Boundary — Content-Plane vs Control-Plane
ADR-0028: Stateless Encrypted Token-State Cookie (no server-side session store)
ADR-0029: Document Content Model — Draft-Freeze, Content-Table RLS, Append-Only Audit
ADR-0030: Review & Life-Cycle Realization Model
ADR-0031: Released-base readability enforcement & copy-on-derive mechanics
ADR-0032: Frontend realization — Quinoa, Angular Material, i18n & E2E
ADR-0033: CSRF control for the BFF session — SameSite + JSON content-type
ADR-0034: Notification realization — in-process domain events + system-context fan-out
ADR-0035: Fan-out contract as shipped — gate semantics, count disclosure, audit protocol
ADR-0036: Repository layer — services carry rules, repositories carry jOOQ
ADR-0037: Task scheduler — in-process tick, advisory-lock election, SQL sweep
ADR-0038: Periodic-review realization — derived due date, policy-gated confirmation
ADR-0039: Sweep & periodic-review contract as shipped — grants, guards, addressing
ADR-0040: Disposal-due surfacing — closure-anchored retention, scope-level legal hold
ADR-0041: Email channel & notification i18n — notification-as-outbox, structured messages
ADR-0042: Disposal execution — document tombstoning, single-actor hard-gated destruction
ADR-0043: Disposal blob deletion is post-commit, GC-backstopped
ADR-0044: Search FTS baseline — event-indexed, RLS-scoped search_index
ADR-0045: Image Attachments as Content Parts (Rich-Content Slice R2)
ADR-0046: Four-Eyes — Submitter Excluded from Approval
ADR-0047: Four-Eyes — Submitter-Only Exclusion
ADR-0048: Document Organization — Folder Tree per Scope
ADR-0049: Content Model Round 2 — Type Categories, Template Instantiation, Trace Relations, Completeness Rules
ADR-0050: Live Frontend — SSE State Push, CodeMirror 6, Draft Presence
ADR-0051: In-Text Document Links (doc: Scheme)
ADR-0052: Addressees & Read-Acknowledgement (REQ-TRN Realization)
ADR-0053: Addressees Per Document + Process Owner (amends ADR-0052 K-1)
ADR-0054: Process Owner Is a Role (amends ADR-0053 P-3)
ADR-0055: WYSIWYG Editing Mode over Markdown (editor step R4)
ADR-0056: Visual-Editor Chrome via Milkdown Crepe (gated adoption)
ADR-0057: Content Record Is the ProseMirror Document Tree; Markdown Becomes a Derived Projection
ADR-0058: PM_DOC Is the Only Content Format (pre-production cut; amends ADR-0057 §5)
ADR-0059: Editor Engine Switches to TipTap (spike-gated; supersedes the Milkdown/Crepe choice)
ADR-0060: Backup & Restore — Scripted Ordered Backup with Automated Restore Rehearsal
ADR-0061: CSV — Generated Validation Package per Release
ADR-0062: SBOM — CycloneDX over the Production Layers, Validated Against the Artifact
ADR-0063: User Identity Binds on Subject Only (Issuer Becomes Provenance)
ADR-0064: Per-Document Workflow Role Bindings (Author / Reviewer / Releaser), Enforced
ADR-0065: Diagrams — Excalidraw as the Manual Layer, Mermaid Stays for Text-First/UML
ADR-0066: WITHDRAW — the Author Side May Reclaim a Version from Review
ADR-0067: Review Comments — Anchored, Immutable, Resolvable
ADR-0068: Confluence/Jira QMS Import — Staged, Read-Only, Repeatable
ADR-0069: Arbitrary File Attachments — Download-Only Confinement
ADR-0070: Training Questionnaires — Versioned, Auto-Scored, Release-Gated
ADR-0071: Training Plans — Document Obligations + External Trainings & Certifications
ADR-0072: Diagrams — Self-Hosted draw.io Replaces Excalidraw
ADR-0073: Per-Scope QMS Configuration Surface
ADR-0074: PDF Export of Released Documents — Server-Side via Apache FOP over the Canonical Projection
ADR-0075: Source History Import — Continuity Without Forged Audit
ADR-0076: Periodic-review status visibility (completing MVP gap #2)
ADR-0077: Requirement Items — Keyed Blocks Inside Controlled Documents
ADR-0078: Generalized Trace Items (Traceability Model — Stage A)
ADR-0079: Risk & Risk-Control Items (Traceability Model — Stage B)
ADR-0080: Traceability Workspace — Hub, Sub-Pages, and Role-Gated Views
ADR-0081: Draft-Only Trace-Structure Changes, Server-Enforced
ADR-0082: Table-Shaped Risk Authoring over Risk Blocks
ADR-0083: The TD Dossier — a Versioned, Cross-Scope, Regulatory-Structured Deliverable
ADR-0084: Validation & Regulatory Axes (Traceability Model — Stage C)
ADR-0085: Relation-Layer Consolidation — One Trace Vocabulary, One Surface
ADR-0086: Requirement Traceability Chains — End-to-End Path View + Flat Path Export
ADR-0087: The Scope Traceability Report — One Derived Overview Artifact, Never a Controlled Document
ADR-0088: Verification Evidence Classes — Planned vs. Verified, Derived at the Read Layer
ADR-0089: Recurring Obligations — Periodic Tasks With Record Evidence, Not Calendar Series
ADR-0090: Release & Versioning Policy — Deliberate Releases, One Auditor-Facing Number
ADR-0091: Release Modes — Single-Person Record Release With a Structural Four-Eyes Floor
ADR-0092: Orphan-Blob Garbage Collection With a Quarantine Bin
ADR-0092: Orphan-Blob Garbage Collection With a Quarantine Bin
Table of contents
Decision
Consequences
Amendment 2026-07-25 — the quarantine row is the deletion MUTEX (review finding A3)
Known limitation (recorded 2026-08-21, ruled 2026-08-23 — amendment deferred past 1.0)
ADR-0093: One Scope Context — the Toolbar Switcher Is the Only Scope Selector
ADR-0094: Calendar-Anchored Obligation Schedules (Clamped, Never Too Late)
ADR-0095: Key-Rule Governance — Free Until First Use, Then Frozen
ADR-0096: Transition Permissions — Always Visible, Deny Unless Granted
ADR-0097: A Governed Provisioning Surface — MANAGE_SCOPES
ADR-0098: Org Chart × Role System — Marriage at the Evidence Level, Never in Authorization
ADR-0099: The User Manual is an In-App Topic Reference, Not a Document
ADR-0100: LQMS Is the Living Quality Management System
ADR-0101: The Executable Validation Journey (PQ Evidence That Cannot Drift)
ADR-0102: Typed Template Variables (text | date | number — and Deliberately No Enum)
ADR-0103: npm audit Joins the Verification Gate as a Second Standing Input
ADR-0104: The Issued Dossier Is a Persisted Artifact of Record — and Clones to a New Draft
ADR-0105: Navigation Information Architecture — Group by Moment-of-Use
ADR-0106: The Client Reflection Follows Assignments, Not Only Content Reach
ADR-0107: The Audit Append Gate Follows Assignment Reach, Not Content Reach
ADR-0108: Mandator Membership — Invite-Accept, with Pre-Assigned Responsibilities
ADR-0109: Organization Founding Is Its Own Process
ADR-0110: The Audit Trail Is Not a Read Model
ADR-0111: The Imported-Person Model, and Project Portability's First Doctrines
ADR-0112: The Element-Kind Catalog — Semantics in the Model, Not Only in the Code
ADR-0113: Project Arrival Import — Records Arrive as They Are, People Arrive as They Were
ADR-0114: The Operating Model Arrives — Roles as Functions, Names as Words, People as This Instance's Decision
ADR-0115: Collaborative Draft Editing — Two Carets, One Truth, Honest Credit
ADR-0116: The System Maintenance Surface — the App Backs Itself Up, the Host Keeps One Dumb Job
ADR-0117: Role Documentation — a Link, a Finding, Per-Source Recognizers; Substitution Rejected
ADR-0118: The Offline QMS Copy — the Repo Carries the Audit Pack, Not a Second Renderer
ADR-0119: Module-Internal Package Structure — Capabilities First, Layers Second, the Root Is the Surface
ADR-0120: The Shared Kernel — the Domain-Exception Vocabulary Leaves the Authorization Module
ADR-0121: The Project Administrator Role — Per-Scope Administration With Read Access, Seeded in the Base Catalog
ADR-0122: Organization-Level Administration — the Cascade Stays, Becomes Visible, and Founds Projects
ADR-0123: Draft Save-Points — Every Save Restorable, Kept for the Life of the Version
ADR-0124: The Birth Path Completes Without Borrowing Content Clothes
ADR-0125: The Export Twin — Export Emits an Arrival Bundle
ADR-0126: Project Dissolution — the Un-Birth of an Unused Scope
ADR-0127: The Base-QMS Layers — One Library, Derived Adaptations, Local Records
ADR-0128: The GLOBAL Cascade Carries Administration, Never Content
ADR-0129: Role Identity from a GLOBAL Assignment Acts in GLOBAL Alone
ADR-0130: Break-Glass — the Project Administrator's Escalation Is a First-Class, Witnessed, Self-Expiring Act
ADR-0131: Role Substitution as Declared Adoption Edges — Emergency Cover Is Governed, Own-Name, Timed Staffing
ADR-0132: Dual-Hat Reviewer Satisfaction Is a Declared Policy Choice — the Strict Floor Stays the Default
ADR-NNNN:
</span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_5" > <div class="md-nav__link md-nav__container"> <a href="../../requirements/" class="md-nav__link "> <span class="md-ellipsis"> Requirements </span> </a> <label class="md-nav__link " for="__nav_5" id="__nav_5_label" tabindex="0"> <span class="md-nav__icon md-icon"></span> </label> </div> <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_5_label" aria-expanded="false"> <label class="md-nav__title" for="__nav_5"> <span class="md-nav__icon md-icon"></span> Requirements </label> <ul class="md-nav__list" data-md-scrollfix> <li class="md-nav__item"> <a href="../../requirements/stakeholder_requirements/" class="md-nav__link"> <span class="md-ellipsis"> Stakeholder Requirements </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/gap-analysis/" class="md-nav__link"> <span class="md-ellipsis"> Requirements Gap Analysis </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_admin/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Administration, Permissions & Onboarding </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_api_ui/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: API & User Interface </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_audit_reporting/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Audit Trail & Regulatory Reporting </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_auth/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Authentication & Session </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_backup/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Backup & Restore </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_catalogs/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Catalogs, Roles & Users </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_data_protection/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Data Protection, Retention & Disposal </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_documents/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Documents, Versions & Storage </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_dossiers/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Technical Documentation Dossiers </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_effectivity/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Effectivity, Periodic Review & Validity </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_gspr/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Regulatory Conformity (GSPR / Essential Principles) </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_i18n/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Internationalization </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_lifecycle/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Life Cycle & Reviews </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_memberships/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Mandator Membership & Invitations </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_migration/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Migration & Import </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_nfr/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Non-Functional </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_notifications/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Notifications & Tasks </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_obligations/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Recurring Obligations </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_relationships/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Document Relationships </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_risk/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Risk Management (ISO 14971 Hazards & Controls) </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_sbom/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Software Bill of Materials & Supply-Chain Assurance </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_search/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Search </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_separation/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Scopes, Mandators & Separation </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_signatures/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Electronic Signatures </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_training/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Read-Acknowledgement & Questionnaires </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_users/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: User Identity & Lifecycle </span> </a> </li> <li class="md-nav__item"> <a href="../../requirements/req_validation/" class="md-nav__link"> <span class="md-ellipsis"> Software Requirements: Design Validation & the Validation Traceability Axis </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_6" > <div class="md-nav__link md-nav__container"> <a href="../../process/" class="md-nav__link "> <span class="md-ellipsis"> Process (IEC 62304) </span> </a> <label class="md-nav__link " for="__nav_6" id="__nav_6_label" tabindex="0"> <span class="md-nav__icon md-icon"></span> </label> </div> <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_6_label" aria-expanded="false"> <label class="md-nav__title" for="__nav_6"> <span class="md-nav__icon md-icon"></span> Process (IEC 62304) </label> <ul class="md-nav__list" data-md-scrollfix> <li class="md-nav__item"> <a href="../../process/configuration_management_plan/" class="md-nav__link"> <span class="md-ellipsis"> Configuration Management Plan </span> </a> </li> <li class="md-nav__item"> <a href="../../process/problem_resolution/" class="md-nav__link"> <span class="md-ellipsis"> Problem Resolution Process </span> </a> </li> <li class="md-nav__item"> <a href="../../process/risk_management/" class="md-nav__link"> <span class="md-ellipsis"> Risk Management </span> </a> </li> <li class="md-nav__item"> <a href="../../process/software_development_plan/" class="md-nav__link"> <span class="md-ellipsis"> Software Development Plan </span> </a> </li> <li class="md-nav__item"> <a href="../../process/verification_plan/" class="md-nav__link"> <span class="md-ellipsis"> Verification Plan </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_7" > <label class="md-nav__link" for="__nav_7" id="__nav_7_label" tabindex="0"> <span class="md-ellipsis"> Operations </span> <span class="md-nav__icon md-icon"></span> </label> <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_7_label" aria-expanded="false"> <label class="md-nav__title" for="__nav_7"> <span class="md-nav__icon md-icon"></span> Operations </label> <ul class="md-nav__list" data-md-scrollfix> <li class="md-nav__item"> <a href="../../operations/genesis-installation/" class="md-nav__link"> <span class="md-ellipsis"> Genesis: Birthing an LQMS Installation with a Base Library </span> </a> </li> <li class="md-nav__item"> <a href="../../operations/deployment/" class="md-nav__link"> <span class="md-ellipsis"> LQMS Deployment Guide </span> </a> </li> <li class="md-nav__item"> <a href="../../operations/server-deployment/" class="md-nav__link"> <span class="md-ellipsis"> LQMS Server Deployment (single Linux host, public HTTPS) </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_8" > <div class="md-nav__link md-nav__container"> <a href="../../traceability/" class="md-nav__link "> <span class="md-ellipsis"> Traceability </span> </a> <label class="md-nav__link " for="__nav_8" id="__nav_8_label" tabindex="0"> <span class="md-nav__icon md-icon"></span> </label> </div> <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_8_label" aria-expanded="false"> <label class="md-nav__title" for="__nav_8"> <span class="md-nav__icon md-icon"></span> Traceability </label> <ul class="md-nav__list" data-md-scrollfix> <li class="md-nav__item"> <a href="../../traceability/matrix/" class="md-nav__link"> <span class="md-ellipsis"> Requirements Traceability Matrix </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_9" > <div class="md-nav__link md-nav__container"> <a href="../../validation/" class="md-nav__link "> <span class="md-ellipsis"> Validation (tool lane) </span> </a> <label class="md-nav__link " for="__nav_9" id="__nav_9_label" tabindex="0"> <span class="md-nav__icon md-icon"></span> </label> </div> <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_9_label" aria-expanded="false"> <label class="md-nav__title" for="__nav_9"> <span class="md-nav__icon md-icon"></span> Validation (tool lane) </label> <ul class="md-nav__list" data-md-scrollfix> <li class="md-nav__item"> <a href="../../validation/templates/ai-authorship-posture/" class="md-nav__link"> <span class="md-ellipsis"> AI-Authorship Posture — How LQMS Is Built, and Why the Validation Evidence Does Not Rest on It (TEMPLATE) </span> </a> </li> <li class="md-nav__item"> <a href="../../validation/templates/intended-use/" class="md-nav__link"> <span class="md-ellipsis"> Intended-Use Specification — LQMS as a QMS / Document-Control Tool (TEMPLATE) </span> </a> </li> <li class="md-nav__item"> <a href="../../validation/templates/tool-risk-assessment/" class="md-nav__link"> <span class="md-ellipsis"> Tool-Risk Assessment — LQMS as a QMS Tool (TEMPLATE) </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_10" > <label class="md-nav__link" for="__nav_10" id="__nav_10_label" tabindex="0"> <span class="md-ellipsis"> Regulatory </span> <span class="md-nav__icon md-icon"></span> </label> <nav class="md-nav" data-md-level="1" aria-labelledby="__nav_10_label" aria-expanded="false"> <label class="md-nav__title" for="__nav_10"> <span class="md-nav__icon md-icon"></span> Regulatory </label> <ul class="md-nav__list" data-md-scrollfix> <li class="md-nav__item"> <a href="../../regulatory/mdr-annex-i-skeleton/" class="md-nav__link"> <span class="md-ellipsis"> MDR Annex I — GSPR authoring skeleton (paraphrased) </span> </a> </li> </ul> </nav> </li> <li class="md-nav__item md-nav__item--nested"> <input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_11" > <div class="md-nav__link md-nav__container"> <a 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<span class="md-ellipsis"> Consequences </span> </a> </li> <li class="md-nav__item"> <a href="#amendment-2026-07-25--the-quarantine-row-is-the-deletion-mutex-review-finding-a3" class="md-nav__link"> <span class="md-ellipsis"> Amendment 2026-07-25 — the quarantine row is the deletion MUTEX (review finding A3) </span> </a> </li> <li class="md-nav__item"> <a href="#known-limitation-recorded-2026-08-21-ruled-2026-08-23--amendment-deferred-past-10" class="md-nav__link"> <span class="md-ellipsis"> Known limitation (recorded 2026-08-21, ruled 2026-08-23 — amendment deferred past 1.0) </span> </a> </li> </ul> </nav> </div> </div> </div> <div class="md-content" data-md-component="content"> <article class="md-content__inner md-typeset"> <a href="https://github.com/nburri/lqms/edit/main/docs/decisions/adr-0092-orphan-blob-gc.md" title="Edit this page" class="md-content__button md-icon"> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M10 20H6V4h7v5h5v3.1l2-2V8l-6-6H6c-1.1 0-2 .9-2 2v16c0 1.1.9 2 2 2h4zm10.2-7c.1 0 .3.1.4.2l1.3 1.3c.2.2.2.6 0 .8l-1 1-2.1-2.1 1-1c.1-.1.2-.2.4-.2m0 3.9L14.1 23H12v-2.1l6.1-6.1z"/></svg> </a> <h1 id="adr-0092-orphan-blob-garbage-collection-with-a-quarantine-bin">ADR-0092: Orphan-Blob Garbage Collection With a Quarantine Bin<a class="headerlink" href="#adr-0092-orphan-blob-garbage-collection-with-a-quarantine-bin" title="Permanent link">¶</a></h1> <ul> <li><strong>Status:</strong> accepted (Nicolas 2026-07-22 — GAP-row decision "2a", with the bin refinement: "potentially using a 'bin' to soft delete orphaned blobs and only to delete them permanently after a certain time, e.g. 30 days in the bin")</li> <li><strong>Date:</strong> 2026-07-22</li> <li><strong>Deciders:</strong> Nicolas Burri, design by Claude. Origin: the 2026-07-22 GAP investigation found that REQ-DOC-013's GC job does not exist, while <code>DisposalService</code> (ADR-0042) explicitly relies on it — its post-commit blob deletion logs failures and continues on the promise that "orphan garbage collection sweeps any leftover blob (ADR-0025)". Orphans currently leak forever.</li> <li><strong>Relates to:</strong> ADR-0001 (content-addressed store), ADR-0025 (disposal/erasure mechanics — the GC assumption this ADR discharges), ADR-0042 (disposal execution), ADR-0037 (scheduler/sweep election pattern).</li> <li><strong>Requirement:</strong> REQ-DOC-013 — "A garbage-collection job shall remove blobs no longer referenced by any version; referenced blobs shall never be deleted."</li> </ul> <h2 id="decision">Decision<a class="headerlink" href="#decision" title="Permanent link">¶</a></h2> <ol> <li><strong>Two-phase deletion — quarantine, then purge.</strong> A blob is never removed from disk the first time it is seen unreferenced. Phase 1 (quarantine): a periodic sweep records each orphan in a <code>blob_quarantine</code> registry (scope, hash, quarantined_at). Phase 2 (purge): a later sweep pass permanently deletes a quarantined blob only after it has sat in the bin for the configured quarantine period (default <strong>30 days</strong>, configurable) <strong>and</strong> is re-verified unreferenced at purge time.</li> <li><strong>The bin is a registry, not a file move.</strong> Quarantined blob bytes stay physically in place in the content store; only the registry row marks them. This keeps the content-addressed store's invariants intact: an idempotent <code>put</code> of the same content (re-reference through dedup) simply works, <code>get</code> never breaks, and rescue is a registry-row delete. Any sweep pass that finds a quarantined hash referenced again removes it from the bin (rescue) — the safety re-check at purge time makes even a missed rescue harmless.</li> <li><strong>Reference truth is the database, enumerated explicitly.</strong> A blob is live when its hash is referenced by any non-disposed row of a blob-referencing column. The implementation enumerates these columns in one place (the GC's reference query), and an architecture test asserts the schema's set of hash-carrying blob-reference columns equals that enumeration — adding a new blob-referencing column then fails the test until the GC inventory is extended (the schema-extension lifecycle trap, made structural).</li> <li><strong>Safety invariant, structurally enforced:</strong> referenced blobs are never deleted. Both phases run their reference check and the registry mutation in one transaction; physical file deletion happens post-commit (the ADR-0042 pattern), is idempotent, and a failed file deletion simply leaves an orphan that the next sweep re-quarantines — the mechanism is self-healing in both directions.</li> <li><strong>Scheduling and observability:</strong> a nightly scheduler tick (advisory-lock election, the ADR-0037 <code>TaskSweep</code> pattern — every instance ticks, one sweeps). Each pass logs per-scope counts (quarantined, rescued, purged); a purge that actually deletes blobs writes an audit event with the counts, so the destructive act is visible in the trail without flooding it on idle nights.</li> </ol> <h2 id="consequences">Consequences<a class="headerlink" href="#consequences" title="Permanent link">¶</a></h2> <ul> <li>Additive migration (<code>blob_quarantine</code>), a <code>list(scope)</code> enumeration on <code>ContentStore</code> (the filesystem implementation walks its scope directory), the sweep service + scheduler, config for period and quarantine duration, tests incl. the never-delete-referenced invariant, the quarantine round-trip (orphan → bin → rescue on re-reference; orphan → bin → purge after expiry) and the column-inventory architecture test.</li> <li>Discharges the <code>DisposalService</code> post-commit failure path's standing assumption; REQ-DOC-013 flips from GAP to verified via the new tests.</li> <li>No user-facing surface for the MVP: the bin is an operational safety net, not a restore feature; rescue is automatic (re-reference), not manual.</li> </ul> <h2 id="amendment-2026-07-25--the-quarantine-row-is-the-deletion-mutex-review-finding-a3">Amendment 2026-07-25 — the quarantine row is the deletion MUTEX (review finding A3)<a class="headerlink" href="#amendment-2026-07-25--the-quarantine-row-is-the-deletion-mutex-review-finding-a3" title="Permanent link">¶</a></h2> <ul> <li><strong>Status:</strong> amendment implemented 2026-07-25 (Opus 5 review round, finding A3 — HIGH, data-loss class); <strong>RATIFIED by Nicolas 2026-07-26</strong> ("the ADR looks good"). It refines the <em>mechanism</em> of §4 in order to keep §4's own safety invariant ("referenced blobs are never deleted"). The decision itself — two-phase bin, registry not file move, DB reference truth, nightly election — is unchanged.</li> </ul> <p><strong>What was wrong.</strong> §4 said both phases run their reference check and the registry mutation in one transaction, with physical deletion post-commit (the ADR-0042 pattern). The re-check was a <em>snapshot reuse</em>, not a re-read: one live-set read served quarantine, rescue and purge, so "re-verified unreferenced at purge time" was tautological. Worse, post-commit deletion cannot be made safe by re-checking harder. <code>put</code> is content-addressed and DEDUPS (byte-identical content writes nothing), so a concurrent upload can commit a live reference to a hash between the check and the file deletion — the reference survives, the bytes do not, including under a frozen content part of a RELEASED record. The same shape existed in <code>DisposalService</code>'s post-commit deletion.</p> <p><strong>The amendment.</strong></p> <ol> <li><strong>The quarantine row is a mutex, and both sides take it.</strong> A blob's file is deleted only by a transaction that first CLAIMED its bin row (a <code>DELETE … RETURNING</code>), and the deletion happens INSIDE that transaction, while the claim's row lock is held. A guarded write (<code>BlobGcGuard.put</code>) deletes the same row as its RESCUE, on the writer's own transaction. For a given (scope, hash) exactly one side wins: the claimer (the writer then blocks, finds no row, and re-materializes its bytes — the SELF-HEAL), or the writer (the row is gone, the hash is never claimed, the file is never touched).</li> <li><strong>The purge re-reads liveness against the claim</strong> — a fresh statement snapshot under READ COMMITTED, not the pass's opening snapshot. A claimed hash found live again is rescued instead of purged.</li> <li><strong>Every production blob write goes through the guard</strong> (<code>BlobGcGuard.put</code>): freeze body/tree/manifest, attachment upload, derive attachment copy, training evidence. A bare <code>ContentStore.put</code> is a write outside the protocol.</li> <li><strong>Disposal marks before it destroys.</strong> The severed-and-unreferenced hashes enter the bin INSIDE the disposal transaction and are destroyed immediately after it commits, through the same claim+purge primitive. Erasure stays prompt (no 30-day wait) and stays outside the disposal transaction, so a storage error still cannot roll back a committed tombstone; a failure now leaves the blobs quarantined with their purge clock already started instead of as unnoticed orphans.</li> </ol> <p><strong>Consequence for §4.</strong> "Physical file deletion happens post-commit" no longer holds for the GC purge: post-commit deletion drops the mutex before the destructive act. The ADR-0042/0043 rationale for post-commit deletion — never roll back a committed, audited tombstone because of a transient storage error — does not apply to the GC, which has no tombstone to protect: a purge that rolls back simply leaves the blob quarantined for the next sweep. Self-healing in both directions is unchanged; a failed file delete leaves an orphan the next sweep re-quarantines.</p> <p><strong>Residual, accepted.</strong> The claim is a blocking <code>DELETE</code>, so a deadlock is theoretically possible when one transaction writes two blobs whose expired bin rows a purge is claiming in the opposite order. PostgreSQL detects it and aborts one transaction; nothing is deleted unsafely and the sweep retries on the next tick. <code>SELECT … FOR UPDATE SKIP LOCKED</code> would remove even that, but PostgreSQL requires the UPDATE privilege for row locking (verified empirically against <code>postgres:18-alpine</code>), and V065 deliberately withheld UPDATE on <code>blob_quarantine</code> to keep bin rows immutable. Not worth a grant-widening migration for a race this narrow.</p> <p><strong>Still on the old pattern (registered follow-up).</strong> Three lower-traffic deletion paths still delete post-commit without the mutex and carry the same (smaller) window: attachment replace/delete (<code>AttachmentService</code>), reject/cancel orphan reclamation (<code>DocumentService.deleteOrphanBlobsBestEffort</code>, called from <code>LifecycleService</code>), and training-evidence delete (<code>TrainingPlanService</code>). They now have the primitive to adopt — <code>mark</code> in the transaction, <code>claim</code> + <code>purgeClaimed</code> after it — and adopting it is mechanical; it was left out of the A3 fix to keep that change reviewable.</p> <h2 id="known-limitation-recorded-2026-08-21-ruled-2026-08-23--amendment-deferred-past-10">Known limitation (recorded 2026-08-21, ruled 2026-08-23 — amendment deferred past 1.0)<a class="headerlink" href="#known-limitation-recorded-2026-08-21-ruled-2026-08-23--amendment-deferred-past-10" title="Permanent link">¶</a></h2> <p>The quarantine mutex covers two orderings; a third exists that it does not: a writer whose <code>put</code>, rescue and existence check ALL run before the deleter's <code>mark</code>, and whose reference commits after the purge, still loses its bytes — <code>purgeClaimed</code>'s liveness re-read cannot see an uncommitted INSERT. The exposure requires a write and a delete of the same <code>(scope, hash)</code> interleaving within one transaction window; it is registered as RISK-005's residual. The fix is a shared lock on <code>(scope, hash)</code> taken by <code>put</code> as well — a contract change every blob caller inherits, which is why Nicolas ruled it a deliberate post-1.0 amendment rather than a rushed one. 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