music_library/backlog/tasks/ml-169.2 - Phase-4-Performance-low-hanging-fruit-audit.md

id, title, status, assignee, created_date, updated_date, labels, dependencies, references, parent_task_id, priority

id	title	status	assignee	created_date	updated_date	labels	dependencies	references	parent_task_id	priority
ML-169.2	Phase 4: Performance low-hanging fruit audit	To Do		2026-05-08 08:59	2026-05-11 06:46	audit ready		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	ML-169	medium

Description

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

Acceptance Criteria

• #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