perf(library): index local lossless albums

src-tauri/crates/psysonic-library/migrations/021_lossless_album_browse_index.sql

@@ -0,0 +1,8 @@
+-- Drive Lossless Albums from the small suffix-qualified candidate set instead
+-- of scanning every album track on large mixed-format libraries.
+CREATE INDEX IF NOT EXISTS idx_track_lossless_album_browse
+  ON track(server_id, suffix COLLATE NOCASE, library_id, album_id)
+  WHERE deleted = 0
+    AND album_id IS NOT NULL
+    AND album_id != ''
+    AND suffix IS NOT NULL;

src-tauri/crates/psysonic-library/src/lossless_albums.rs

@@ -62,21 +62,7 @@ pub fn list_lossless_albums(
     let where_sql = where_clauses.join(" AND ");
     let la_artist = crate::album_compilation_filter::sql_track_group_display_artist("la");
     let sql = format!(
-        "SELECT \
-           la.server_id, \
-           la.album_id, \
-           COALESCE(a.name, la.album_name), \
-           COALESCE(a.artist, {la_artist}), \
-           COALESCE(a.artist_id, la.artist_id), \
-           COALESCE(a.song_count, la.track_count), \
-           COALESCE(a.duration_sec, la.duration_sec), \
-           COALESCE(a.year, la.year), \
-           COALESCE(a.genre, la.genre), \
-           COALESCE(a.cover_art_id, la.cover_art_id), \
-           COALESCE(a.starred_at, la.starred_at), \
-           COALESCE(a.synced_at, la.synced_at), \
-           a.raw_json \
-         FROM ( \
+        "WITH lossless_album AS ( \
            SELECT \
              t.server_id, \
              t.album_id, \
@@ -89,16 +75,38 @@ pub fn list_lossless_albums(
              MAX(t.cover_art_id) AS cover_art_id, \
              MAX(t.starred_at) AS starred_at, \
              MAX(t.synced_at) AS synced_at, \
-             (SELECT COUNT(*) FROM track c \
-              WHERE c.server_id = t.server_id AND c.album_id = t.album_id AND c.deleted = 0) AS track_count, \
-             (SELECT COALESCE(SUM(c.duration_sec), 0) FROM track c \
-              WHERE c.server_id = t.server_id AND c.album_id = t.album_id AND c.deleted = 0) AS duration_sec, \
              MAX(COALESCE(CAST(json_extract(t.raw_json, '$.bitDepth') AS INTEGER), 0)) AS max_bit_depth \
            FROM track t \
            WHERE {where_sql} \
            GROUP BY t.server_id, t.album_id \
-         ) la \
-         LEFT JOIN album a ON a.server_id = la.server_id AND a.id = la.album_id \
+         ), \
+         album_totals AS ( \
+           SELECT c.server_id, c.album_id, COUNT(*) AS track_count, \
+                  COALESCE(SUM(c.duration_sec), 0) AS duration_sec \
+           FROM track c \
+           INNER JOIN lossless_album la \
+             ON la.server_id = c.server_id AND la.album_id = c.album_id \
+           WHERE c.deleted = 0 \
+           GROUP BY c.server_id, c.album_id \
+         ) \
+         SELECT \
+            la.server_id, \
+           la.album_id, \
+           COALESCE(a.name, la.album_name), \
+           COALESCE(a.artist, {la_artist}), \
+           COALESCE(a.artist_id, la.artist_id), \
+           COALESCE(a.song_count, totals.track_count), \
+           COALESCE(a.duration_sec, totals.duration_sec), \
+           COALESCE(a.year, la.year), \
+           COALESCE(a.genre, la.genre), \
+           COALESCE(a.cover_art_id, la.cover_art_id), \
+           COALESCE(a.starred_at, la.starred_at), \
+           COALESCE(a.synced_at, la.synced_at), \
+           a.raw_json \
+          FROM lossless_album la \
+          INNER JOIN album_totals totals \
+            ON totals.server_id = la.server_id AND totals.album_id = la.album_id \
+          LEFT JOIN album a ON a.server_id = la.server_id AND a.id = la.album_id \
          ORDER BY la.max_bit_depth DESC, \
            COALESCE(a.name, la.album_name) COLLATE NOCASE ASC, \
            la.album_id ASC \

src-tauri/crates/psysonic-library/src/lossless_formats.rs

@@ -7,14 +7,14 @@ pub const LOSSLESS_SUFFIXES: &[&str] = &[
     "flac", "wav", "wave", "aiff", "aif", "dsf", "dff", "ape", "wv", "shn", "tta",
 ];
 
-/// `LOWER(alias.suffix) IN ('flac', …)` for SQL WHERE clauses.
+/// Case-insensitive suffix predicate that can use the lossless browse index.
 pub fn track_is_lossless_sql(table_alias: &str) -> String {
     let list = LOSSLESS_SUFFIXES
         .iter()
         .map(|s| format!("'{s}'"))
         .collect::<Vec<_>>()
         .join(", ");
-    format!("LOWER({table_alias}.suffix) IN ({list})")
+    format!("{table_alias}.suffix COLLATE NOCASE IN ({list})")
 }
 
 /// Album has at least one indexed lossless track (same allowlist as browse).
@@ -50,6 +50,6 @@ mod tests {
         let sql = track_is_lossless_sql("t");
         assert!(sql.contains("'flac'"));
         assert!(sql.contains("'tta'"));
-        assert!(sql.starts_with("LOWER(t.suffix) IN ("));
+        assert!(sql.starts_with("t.suffix COLLATE NOCASE IN ("));
     }
 }

src-tauri/crates/psysonic-library/src/store.rs

@@ -12,7 +12,7 @@ use tauri::Manager;
 ///
 /// Migration checklist (wiring, data backfill, open/swap path):
 /// psysonic-workdocs `ai/agent-rules/08-library-db-migrations.md`.
-pub const LIBRARY_DB_SCHEMA_VERSION: i64 = 20;
+pub const LIBRARY_DB_SCHEMA_VERSION: i64 = 21;
 
 /// One-time data repair after migration 014 (`artist.name_sort`).
 pub(crate) const ARTIST_NAME_SORT_RECONCILE_ID: &str = "artist_name_sort_reconcile_v1";
@@ -66,6 +66,9 @@ pub(crate) const MIGRATION_019_MAINSTAGE_FEED_INDEXES: &str =
 /// Version 20: owner-scoped cache for track, album, and artist user ratings.
 pub(crate) const MIGRATION_020_ENTITY_USER_RATING: &str =
     include_str!("../migrations/020_entity_user_rating.sql");
+/// Version 21: suffix-selective candidate index for local lossless album browse.
+pub(crate) const MIGRATION_021_LOSSLESS_ALBUM_BROWSE_INDEX: &str =
+    include_str!("../migrations/021_lossless_album_browse_index.sql");
 
 /// Embedded migrations. Ordered ascending by `version`; the runner sorts
 /// defensively before applying so the source order can stay readable.
@@ -80,6 +83,7 @@ const MIGRATIONS: &[(i64, &str)] = &[
     (18, MIGRATION_018_ARTIST_SYNCED_INDEX),
     (19, MIGRATION_019_MAINSTAGE_FEED_INDEXES),
     (20, MIGRATION_020_ENTITY_USER_RATING),
+    (21, MIGRATION_021_LOSSLESS_ALBUM_BROWSE_INDEX),
 ];
 
 /// Idempotent repair — also runs after the migration runner on every open so
@@ -101,6 +105,12 @@ pub(crate) fn ensure_entity_user_rating_schema(conn: &Connection) -> rusqlite::R
     conn.execute_batch(MIGRATION_020_ENTITY_USER_RATING)
 }
 
+/// Repairs a partial-v21 open where the migration marker exists but the
+/// additive lossless candidate index was not retained.
+pub(crate) fn ensure_lossless_album_browse_index(conn: &Connection) -> rusqlite::Result<()> {
+    conn.execute_batch(MIGRATION_021_LOSSLESS_ALBUM_BROWSE_INDEX)
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub(crate) enum MigrationOutcome {
     /// Every missing migration was applied (or the DB was already at head).
@@ -682,6 +692,7 @@ fn prepare_write_connection_for_open(conn: &Connection) -> rusqlite::Result<()>
     ensure_genre_tags_schema(conn)?;
     ensure_mainstage_feed_indexes(conn)?;
     ensure_entity_user_rating_schema(conn)?;
+    ensure_lossless_album_browse_index(conn)?;
     checkpoint_wal_conn(conn, "open")?;
     Ok(())
 }