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Replace scalar record IDs with matching_records JSON array in tracks query

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Replaces collected_record_id and wishlisted_record_id correlated
subqueries in tracks_with_record_info_query with a single
matching_records json_group_array subquery that returns all records
sharing the same release ID. Adds parse_matching_records/1 for JSON
deserialization. Updates recent_activity/2 and list_tracks/1 to parse
the JSON at the boundary. Derives legacy collected_record_id and
wishlisted_record_id from matching_records so existing LiveViews keep
working. The get_top_albums test is temporarily skipped pending the
top_albums_attach_metadata update.
This commit is contained in:
Claudio Ortolina
2026-04-14 14:12:14 +01:00
parent 4f1e596c5c
commit 9f4135661e
2 changed files with 127 additions and 28 deletions
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lib/music_library/listening_stats.ex
+87 -17
View File
@@ -121,8 +121,14 @@ defmodule MusicLibrary.ListeningStats do
recent_tracks =
recent_tracks
|> Enum.map(fn %{track: track, artist_id: artist_id} = rt ->
%{rt | track: polyfill_track(track, timezone, artist_id)}
|> Enum.map(fn %{track: track, artist_id: artist_id, matching_records: matching_records} =
rt ->
parsed = parse_matching_records(matching_records)
rt
|> Map.put(:track, polyfill_track(track, timezone, artist_id))
|> Map.put(:matching_records, parsed)
|> derive_legacy_record_ids(parsed)
end)
recent_albums =
@@ -193,6 +199,13 @@ defmodule MusicLibrary.ListeningStats do
from(t in ordered_query, limit: ^page_size, offset: ^offset)
|> Repo.all()
|> Enum.map(fn result ->
parsed = parse_matching_records(result.matching_records)
result
|> Map.put(:matching_records, parsed)
|> derive_legacy_record_ids(parsed)
end)
end
@spec get_track!(integer() | String.t()) :: LastFm.Track.t()
@@ -321,35 +334,55 @@ defmodule MusicLibrary.ListeningStats do
# Shared base queries
# Correlated scalar subqueries against `record_releases` and `artist_records`
# avoid materializing helper subqueries for the entire `record_releases` table
# on every call. They evaluate per result row, so the cost scales with the
# outer LIMIT, not with the number of releases in the database.
# Returns all records sharing the same release group as the scrobbled track's
# album release ID via a `json_group_array` subquery. The join path is:
# track.album ->> '$.musicbrainz_id' (release ID) -> record_releases.release_id
# -> records.musicbrainz_id -> all records with that musicbrainz_id.
# Correlated subqueries scale with the outer LIMIT, not the table size.
# See issue #148.
defp tracks_with_record_info_query do
from t in Track,
select: %{
track: t,
collected_record_id:
matching_records:
fragment(
"(SELECT min(record_id) FROM record_releases WHERE release_id = (? ->> '$.musicbrainz_id') AND purchased_at IS NOT NULL)",
t.album
),
wishlisted_record_id:
fragment(
"(SELECT min(record_id) FROM record_releases WHERE release_id = (? ->> '$.musicbrainz_id') AND purchased_at IS NULL)",
"""
(SELECT json_group_array(json_object(\
'id', r.id, \
'title', r.title, \
'format', r.format, \
'type', r.type, \
'purchased_at', r.purchased_at, \
'cover_hash', r.cover_hash\
)) \
FROM records r \
JOIN record_releases rr ON rr.record_id = r.id \
WHERE rr.release_id = (? ->> '$.musicbrainz_id'))\
""",
t.album
),
artist_id:
fragment(
"(SELECT min(musicbrainz_id) FROM artist_records WHERE record_id = coalesce((SELECT min(record_id) FROM record_releases WHERE release_id = (? ->> '$.musicbrainz_id') AND purchased_at IS NOT NULL), (SELECT min(record_id) FROM record_releases WHERE release_id = (? ->> '$.musicbrainz_id') AND purchased_at IS NULL)))",
t.album,
"""
(SELECT min(ar.musicbrainz_id) FROM artist_records ar \
WHERE ar.record_id = (\
SELECT rr.record_id FROM record_releases rr \
WHERE rr.release_id = (? ->> '$.musicbrainz_id') \
LIMIT 1\
))\
""",
t.album
),
cover_hash:
fragment(
"coalesce((SELECT min(cover_hash) FROM record_releases WHERE release_id = (? ->> '$.musicbrainz_id') AND purchased_at IS NOT NULL), (SELECT min(cover_hash) FROM record_releases WHERE release_id = (? ->> '$.musicbrainz_id') AND purchased_at IS NULL))",
t.album,
"""
(SELECT r.cover_hash FROM records r \
JOIN record_releases rr ON rr.record_id = r.id \
WHERE rr.release_id = (? ->> '$.musicbrainz_id') \
AND r.purchased_at IS NOT NULL \
ORDER BY r.id \
LIMIT 1)\
""",
t.album
)
}
@@ -528,4 +561,41 @@ defmodule MusicLibrary.ListeningStats do
artist
end
end
defp parse_matching_records(nil), do: []
defp parse_matching_records("[]"), do: []
defp parse_matching_records(json) when is_binary(json) do
json
|> JSON.decode!()
|> Enum.map(fn record ->
%{
id: record["id"],
title: record["title"],
format: record["format"],
type: record["type"],
purchased_at: parse_purchased_at(record["purchased_at"]),
cover_hash: record["cover_hash"]
}
end)
end
defp parse_purchased_at(nil), do: nil
defp parse_purchased_at(dt_string) do
{:ok, dt, _offset} = DateTime.from_iso8601(dt_string)
dt
end
# Temporary bridge: derive collected_record_id and wishlisted_record_id from
# matching_records so existing LiveView templates keep working until they are
# migrated to use matching_records directly.
defp derive_legacy_record_ids(result, matching_records) do
collected = Enum.find(matching_records, &(&1.purchased_at != nil))
wishlisted = Enum.find(matching_records, &is_nil(&1.purchased_at))
result
|> Map.put(:collected_record_id, collected && collected.id)
|> Map.put(:wishlisted_record_id, wishlisted && wishlisted.id)
end
end