The index fast path / backfill approach was fundamentally broken:
- Index had no data for most search results → all scored ~35
- Backfill tried to patch in LB data but clobbered index scores
- Different maxPop between passes produced inconsistent rankings
New approach: always fetch ArtistPopularity from LB for every
search (single POST, ~200ms). Merge with index data (take the
higher value for each MBID). This ensures correct ranking
regardless of index coverage.
The fast/slow path distinction is preserved for release groups
and recordings (where index coverage is better), but artist
ranking always uses real LB data.
Added boostWithIndexPopularityRGsAndRecs for the RG/recording-only
index path. Removed backfillArtistPopularity entirely.
yonlu
76c8aee1dd