---
id: ML-169.2
title: "Phase 4: Performance low-hanging fruit audit"
status: To Do
assignee: []
created_date: "2026-05-08 08:59"
updated_date: "2026-05-11 06:46"
labels:
  - audit
  - ready
dependencies: []
references:
  - lib/music_library_web/live/stats_live/index.ex
  - lib/music_library_web/live_helpers/index_actions.ex
  - lib/music_library_web/live_helpers/record_actions.ex
  - .agents/skills/query-reporter/SKILL.md
parent_task_id: ML-169
priority: medium
---

## Description

<!-- SECTION:DESCRIPTION:BEGIN -->

Identify unnecessary DB queries, redundant full-stream reloads, server round trips that could be client-side, missing optimistic UI opportunities, and blocking mount work that could be deferred.

Use QueryReporter skill to capture SQL traces for key page loads as evidence.

Key pre-flagged areas:

- StatsLive.Index: 5 synchronous queries in mount (TTFB impact)
- Display toggle (grid/list): full FTS query when CSS-only suffices
- ScrobbleRulesLive + OnlineStoreTemplateLive: redundant stream_insert + immediate full reload
- ScrobbledTracksLive + StatsLive: full stream reset on every scrobble batch instead of incremental insert
- Search inputs: verify phx-debounce is set
<!-- SECTION:DESCRIPTION:END -->

## Acceptance Criteria

<!-- AC:BEGIN -->

- [ ] #1 SQL traces captured via QueryReporter for /collection, /collection/:id, /stats, /artists/:id
- [ ] #2 Stream reset audit complete: every stream(:name, data, reset: true) call site evaluated for incremental-update alternatives
- [ ] #3 Display toggle (grid/list) evaluated: confirmed whether CSS-only toggle can replace full DB reload
- [ ] #4 StatsLive.Index mount blocking work quantified: 5 queries identified, assign_async feasibility assessed
- [ ] #5 Search input debounce verified: phx-debounce attribute presence checked on all search forms
- [ ] #6 Optimistic UI opportunities identified for delete, form save, toggle operations
- [ ] #7 N+1 audit complete: handle_params, stream rendering, and LiveComponent Repo calls checked
- [ ] #8 Findings report written as a Backlog.md document with file:line references, severity ratings, and fix recommendations
<!-- AC:END -->