ML-169.9: add pagination stream reset fix task

2026-05-19 12:51:29 +01:00
parent e42e28992a
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+---
+id: ML-169.9
+title: "Fix: Full stream resets on pagination within same search"
+status: To Do
+assignee: []
+created_date: "2026-05-19 11:48"
+labels:
+  - perf
+  - fix
+dependencies: []
+references:
+  - >-
+    backlog/documents/doc-27 -
+    Phase-4-Performance-Audit-Low-Hanging-Fruit-Findings.md
+modified_files:
+  - lib/music_library_web/live_helpers/index_actions.ex
+  - lib/music_library_web/live/scrobbled_tracks_live/index.ex
+  - lib/music_library_web/live/artist_live/show.ex
+parent_task_id: ML-169
+priority: medium
+ordinal: 30000
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+
+Optimize stream behavior so that pagination within the same search does not trigger a full `stream(..., reset: true)`. Search and order changes still legitimately need resets.
+
+## Problem
+
+Every search query change, order toggle, or **pagination click** triggers a full `stream(..., reset: true)`. While `reset: true` is correct when the entire dataset changes (new search query), it's unnecessary for pagination within the same search — the existing items don't change, only new ones are appended.
+
+## Files
+
+- `lib/music_library_web/live_helpers/index_actions.ex:89` — `load_and_assign_records` uses `reset: true`
+- `lib/music_library_web/live/scrobbled_tracks_live/index.ex:334` — `load_and_assign_tracks` uses `reset: true`
+- `lib/music_library_web/live/artist_live/show.ex:698-699` — `assign_records` uses `reset: true`
+
+## Fix
+
+Use `stream(..., at: -1)` (append) for "load more" pagination. Only use `reset: true` when search text or order field changes. This requires distinguishing between a "new search" and "same search, next page" in the pagination handler.
+
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+
+<!-- AC:BEGIN -->
+
+- [ ] #1 Pagination to next page appends records without full stream reset
+- [ ] #2 Existing stream items remain visible during pagination
+- [ ] #3 Search query change still triggers full stream reset
+- [ ] #4 Order change still triggers full stream reset
+- [ ] #5 No duplicate records appear after multiple pagination clicks
+<!-- AC:END -->