yellowjacket/.planning/milestones/v1.0-phases/07-backend-performance/07-VERIFICATION.md

phase, verified, status, score

phase	verified	status	score
07-backend-performance	2026-03-04T22:45:00Z	passed	9/9 must-haves verified

Phase 7: Backend Performance Verification Report

Phase Goal: Queue mutations and library loading are fast — single-track queue changes are O(1) instead of O(n), and the library doesn't block startup with a full data fetch Verified: 2026-03-04T22:45:00Z Status: passed Re-verification: No — initial verification

Goal Achievement

Observable Truths

#	Truth	Status	Evidence
1	AddTrack persists a single INSERT + position shift instead of DELETE ALL + batch INSERT	✓ VERIFIED	AddTrack calls q.persistAddTrack(track) (queue.go:368) which does a single InsertQueueTrack (persistence.go:17-23). No commitMutation or persistTracks call.
2	RemoveTrack persists a single DELETE + position shift instead of DELETE ALL + batch INSERT	✓ VERIFIED	RemoveTrack calls q.persistRemoveTrack(position) (queue.go:774) which does RemoveQueueTrackByPosition + ShiftQueuePositionsDown in a transaction (persistence.go:146-192). No commitMutation or persistTracks call.
3	InsertNext/InsertNextTracks/InsertTracksAt persist incremental INSERTs + position shift instead of DELETE ALL + batch INSERT	✓ VERIFIED	InsertNext calls q.persistInsertTracks([]Track{track}, insertPos) (queue.go:526), InsertNextTracks calls q.persistInsertTracks(newTracks, insertPos) (queue.go:476), InsertTracksAt calls q.persistInsertTracks(newTracks, index) (queue.go:593). persistInsertTracks does variable-N position shift + batch INSERT in a transaction (persistence.go:81-141).
4	SetQueue Phase 2 skips file paths already resolved in Phase 1	✓ VERIFIED	resolveRemainingTracks accepts phase1Meta map[string]trackMeta (queue.go:267), filters unresolvedPaths by excluding keys in phase1Meta (queue.go:270-276), calls lookupTrackMetaBatch(unresolvedPaths) only for unresolved paths (queue.go:279), then merges Phase 1 results back in (queue.go:282-284).
5	Bulk operations (SetQueue, Clear, MoveQueueTracks) still use the full DELETE ALL + batch INSERT pattern	✓ VERIFIED	resolveRemainingTracks calls q.commitMutation(false) (queue.go:330), MoveQueueTracks calls q.commitMutation(true) (queue.go:737), Clear calls q.commitMutation(false) (queue.go:1102), RemoveTracks calls q.persistTracks() (queue.go:849). All bulk paths preserved.
6	All existing queue persistence roundtrip tests pass	✓ VERIFIED	go test ./queue/... -race -count=1 passes all 29 tests including persistence roundtrip tests (TestSaveState_RestoreState_Roundtrip, TestSaveState_RestoreState_EmptyQueue, etc.)
7	LibraryStore constructor does NOT call eagerFetch() — app shell renders instantly	✓ VERIFIED	Constructor calls this.deferEagerFetch() (library-store.ts:56) instead of this.eagerFetch() directly. No direct eagerFetch() call in constructor.
8	After DOM is ready, eagerFetch() is called — all 4 data types still loaded eagerly	✓ VERIFIED	deferEagerFetch() listens for DOMContentLoaded event (library-store.ts:70-76) or calls immediately if DOM already parsed (library-store.ts:80). eagerFetch() still calls all 4 getters: getTracks, getAlbums, getArtists, getGenres (library-store.ts:325-330).
9	Post-scan invalidation still calls eagerFetch() to re-fetch everything	✓ VERIFIED	invalidate() method calls this.eagerFetch() directly (library-store.ts:315), not deferred. Scan complete event listener calls this.invalidate() (library-store.ts:51-53).

Score: 9/9 truths verified

Required Artifacts

Artifact	Expected	Status	Details
backend/queue/persistence.go	Incremental persist helpers: persistAddTrack, persistAddTracks, persistInsertTracks, persistRemoveTrack	✓ VERIFIED	All 4 helpers present (lines 16, 30, 81, 146). Contains func (q *Queue) persistAddTrack as required. 475 lines, substantive implementations with transactions, error handling, and SAFETY comments.
backend/queue/queue.go	Updated mutations using incremental persistence; resolveRemainingTracks with exclusion set	✓ VERIFIED	AddTrack (line 368), AddTracks (line 418), InsertNext (line 526), InsertNextTracks (line 476), InsertTracksAt (line 593), RemoveTrack (line 774) all use incremental persist. resolveRemainingTracks accepts phase1Meta and filters with exclusion set (lines 267-284). Contains persistAddTrack as required.
frontend/src/store/library-store.ts	Deferred eagerFetch via DOMContentLoaded event	✓ VERIFIED	Contains deferEagerFetch() method with DOMContentLoaded listener (line 68-82). Constructor calls deferEagerFetch() (line 56) instead of eagerFetch(). Contains EventsOn as required.

Key Link Verification

From	To	Via	Status	Details
queue.go AddTrack	persistence.go persistAddTrack	direct method call	✓ WIRED	q.persistAddTrack(track) at queue.go:368, replaces commitMutation
queue.go RemoveTrack	persistence.go persistRemoveTrack	direct method call	✓ WIRED	q.persistRemoveTrack(position) at queue.go:774, replaces commitMutation
queue.go resolveRemainingTracks	queue.go lookupTrackMetaBatch	exclusion set filtering	✓ WIRED	phase1Meta parameter (queue.go:267), exclusion filter (queue.go:270-276), lookupTrackMetaBatch(unresolvedPaths) (queue.go:279)
library-store.ts constructor	library-store.ts eagerFetch	DOMContentLoaded event	✓ WIRED	this.deferEagerFetch() (line 56) → DOMContentLoaded listener → this.eagerFetch() (lines 68-82)

Requirements Coverage

Requirement	Source Plan	Description	Status	Evidence
PERF-01	07-01-PLAN	Queue single-track mutations use incremental INSERT/DELETE instead of full table rewrite	✓ SATISFIED	AddTrack→persistAddTrack, RemoveTrack→persistRemoveTrack, InsertNext/InsertNextTracks/InsertTracksAt→persistInsertTracks. No commitMutation/persistTracks for single-track ops.
PERF-02	07-01-PLAN	SetQueue Phase 2 skips file paths already resolved in Phase 1	✓ SATISFIED	resolveRemainingTracks filters unresolvedPaths via phase1Meta exclusion set, calls lookupTrackMetaBatch only for unresolved paths, merges Phase 1 results back.
PERF-03	07-02-PLAN	Library store constructor no longer calls eagerFetch(); data loads after DOM ready	✓ SATISFIED	Constructor calls deferEagerFetch() which uses DOMContentLoaded event. eagerFetch() loads all 4 data types eagerly once triggered. invalidate() still calls eagerFetch() directly.

No orphaned requirements — all 3 requirements (PERF-01, PERF-02, PERF-03) from REQUIREMENTS.md traceability table for Phase 7 are accounted for by plans 07-01 and 07-02.

Anti-Patterns Found

File	Line	Pattern	Severity	Impact
—	—	No TODO/FIXME/PLACEHOLDER found	—	—
—	—	No empty implementations found	—	—
—	—	No stub patterns found	—	—

Clean — no anti-patterns detected in any modified files.

Human Verification Required

1. App Shell Renders Before Data Loads

Test: Launch the app and observe whether the UI shell appears before library data populates the views Expected: App shell (sidebar, toolbar, empty views) renders immediately; then tracks/albums/artists/genres populate after a brief delay Why human: Visual render timing cannot be verified programmatically — requires observing paint order

2. Queue Operations Feel Fast on Large Queues

Test: Build a queue with 500+ tracks, then add/remove individual tracks Expected: Single-track add/remove completes noticeably faster than before (no perceptible delay from full table rewrite) Why human: Performance improvement is a feel/perception check, not a binary pass/fail

3. Post-Scan Library Refresh Still Works

Test: Trigger a library scan while the app is running, then verify all views refresh with new data Expected: After scan completes, all 4 views (tracks, albums, artists, genres) show updated data Why human: End-to-end behavior involving backend scan + event emission + frontend refresh cycle

Gaps Summary

No gaps found. All 9 observable truths verified, all 3 artifacts substantive and wired, all 4 key links connected, all 3 requirements satisfied. Backend builds, all 29 queue tests pass with -race, and all 3 commits exist in git history.

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Verified: 2026-03-04T22:45:00Z Verifier: Claude (gsd-verifier)