feat(media): Make variant generation atomic with database
Per v1.5.0 Phase 4: - Generate variants to temp directory first - Perform database inserts in transaction - Move files to final location before commit - Clean up temp files on any failure - Add startup recovery for orphaned temp files - All media operations now fully atomic Changes: - Modified generate_all_variants() to return file moves - Modified save_media() to handle full atomic operation - Add cleanup_orphaned_temp_files() for startup recovery - Added 4 new tests for atomic behavior - Fixed HEIC variant format detection - Updated variant failure test for atomic behavior Fixes: - No orphaned files on database failures - No orphaned DB records on file failures - Startup recovery detects and cleans orphans 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
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docs/design/v1.5.0/2025-12-17-phase3-architect-review.md
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docs/design/v1.5.0/2025-12-17-phase3-architect-review.md
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# Phase 3 Architect Review: N+1 Query Fix
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**Date**: 2025-12-17
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**Phase**: Phase 3 - N+1 Query Fix (Feed Generation)
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**Reviewer**: Claude (StarPunk Architect Agent)
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**Implementation Report**: `2025-12-17-phase3-implementation.md`
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---
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## Review Summary
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**VERDICT: APPROVED**
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Phase 3 implementation meets all acceptance criteria and demonstrates sound architectural decisions. The developer can proceed to Phase 4.
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---
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## Acceptance Criteria Verification
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| Criterion | Status | Notes |
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|-----------|--------|-------|
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| Feed generation uses batch queries | PASS | `_get_cached_notes()` now calls `get_media_for_notes()` and `get_tags_for_notes()` |
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| Query count reduced from O(n) to O(1) | PASS | 3 total queries vs. 1+2N queries previously |
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| No change to API behavior | PASS | Feed output format unchanged, all 920 tests pass |
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| Performance improvement verified | PASS | 13 new tests validate batch loading behavior |
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| Other N+1 locations documented | PASS | BACKLOG.md updated with deferred locations |
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---
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## Implementation Review
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### 1. Batch Media Loading (`starpunk/media.py` lines 728-852)
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**SQL Correctness**: PASS
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- Proper use of parameterized `IN` clause with placeholder generation
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- JOIN structure correctly retrieves media with note association
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- ORDER BY includes both `note_id` and `display_order` for deterministic results
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**Edge Cases**: PASS
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- Empty list returns `{}` (line 750-751)
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- Notes without media receive empty lists via dict initialization (line 819)
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- Variant loading skipped when no media exists (line 786)
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**Data Integrity**: PASS
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- Output format matches `get_note_media()` exactly
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- Variants dict structure identical to single-note function
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- Caption, display_order, and all metadata fields preserved
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**Observation**: The implementation uses 2 queries (media + variants) rather than a single JOIN. This is architecturally sound because:
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1. Avoids Cartesian product explosion with multiple variants per media
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2. Keeps result sets manageable
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3. Maintains code clarity
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### 2. Batch Tag Loading (`starpunk/tags.py` lines 146-197)
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**SQL Correctness**: PASS
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- Single query retrieves all tags for all notes
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- Proper parameterized `IN` clause
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- Alphabetical ordering preserved: `ORDER BY note_tags.note_id, LOWER(tags.display_name) ASC`
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**Edge Cases**: PASS
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- Empty list returns `{}` (line 169-170)
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- Notes without tags receive empty lists (line 188)
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**Data Integrity**: PASS
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- Returns same `{'name': ..., 'display_name': ...}` structure as `get_note_tags()`
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### 3. Feed Generation Update (`starpunk/routes/public.py` lines 38-86)
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**Integration**: PASS
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- Batch functions called after note list retrieval
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- Results correctly attached to Note objects via `object.__setattr__`
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- Cache structure unchanged (notes list still cached)
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**Pattern Consistency**: PASS
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- Uses same attribute attachment pattern as existing code
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- `media` attribute and `_cached_tags` naming consistent with other routes
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### 4. Test Coverage (`tests/test_batch_loading.py`)
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**Coverage Assessment**: EXCELLENT
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- 13 tests covering all critical scenarios
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- Empty list handling tested
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- Mixed scenarios (some notes with/without media/tags) tested
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- Variant inclusion verified
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- Display order preservation verified
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- Tag alphabetical ordering verified
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- Integration with feed generation tested
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**Test Quality**:
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- Tests are isolated and deterministic
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- Test data creation is clean and well-documented
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- Assertions verify correct data structure, not just existence
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---
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## Architectural Observations
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### Strengths
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1. **Minimal Code Change**: The implementation adds functionality without modifying existing single-note functions, maintaining backwards compatibility.
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2. **Consistent Patterns**: Both batch functions follow identical structure:
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- Empty check early return
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- Placeholder generation for IN clause
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- Dict initialization for all requested IDs
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- Result grouping loop
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3. **Performance Characteristics**: The 97% query reduction (101 to 3 for 50 notes) is significant. SQLite handles IN clauses efficiently for the expected note counts (<100).
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4. **Defensive Coding**: Notes missing from results get empty lists rather than KeyErrors, preventing runtime failures.
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### Minor Observations (Not Blocking)
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1. **f-string SQL**: The implementation uses f-strings to construct IN clause placeholders. While safe here (placeholders are `?` characters, not user input), this pattern requires care. The implementation is correct.
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2. **Deferred Optimizations**: Homepage and tag archive pages still use per-note queries. This is acceptable per RELEASE.md scope, and the batch functions can be reused when those are addressed.
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3. **No Query Counting in Tests**: The performance test verifies result completeness but does not actually count queries. This is acceptable because:
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- SQLite does not provide easy query counting
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- The code structure guarantees query count by design
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- A query counting test would add complexity without proportional value
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---
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## Standards Compliance
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| Standard | Status |
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|----------|--------|
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| Python coding standards | PASS - Type hints, docstrings present |
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| Testing checklist | PASS - Unit, integration, edge cases covered |
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| Documentation | PASS - Implementation report comprehensive |
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| Git practices | PASS - Clear commit message with context |
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---
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## Recommendation
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Phase 3 is **APPROVED**. The implementation:
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1. Achieves the stated performance goal
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2. Maintains full backwards compatibility
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3. Follows established codebase patterns
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4. Has comprehensive test coverage
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5. Is properly documented
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The developer should proceed to **Phase 4: Atomic Variant Generation**.
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---
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## Project Plan Update
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Phase 3 acceptance criteria should be marked complete in RELEASE.md:
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```markdown
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#### Acceptance Criteria
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- [x] Feed generation uses batch queries
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- [x] Query count reduced from O(n) to O(1) for media/tags
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- [x] No change to API behavior
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- [x] Performance improvement verified in tests
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- [x] Other N+1 locations documented in BACKLOG.md (not fixed)
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```
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---
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**Architect**: Claude (StarPunk Architect Agent)
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**Date**: 2025-12-17
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**Status**: APPROVED - Proceed to Phase 4
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