The autotag overhaul added cover-art and MusicBrainz-ID columns to
leanTrackQuery to support the new track-row styling, reintroducing the
per-row correlated subquery anti-pattern (artist_mbid) plus a cover_art
join inside the whole-library derived table. Both ran for every track
before WHERE/LIMIT, so smart-playlist evaluation cost scaled with
library size rather than result size — several seconds for a 500-track
playlist that was previously sub-second.
Move these presentation-only fields into a batched fetchArtwork pass
keyed by the matched recording_ids, mirroring the existing fetchGenres
batch. Cost is now proportional to results. Add TestEvaluate_ArtworkEnrichment
(no prior coverage of these fields) and an artwork_ms debug metric.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
yonluandClaude Opus 4.8
16886c92cf