Update sizes with SQL, instead of a full rescan

db/migration/20201010162350_add_album_size.go

@@ -16,12 +16,15 @@ alter table album
 	add size integer default 0 not null;
 create index if not exists album_size
 	on album(size);
-	`)
-	if err != nil {
-		return err
-	}
-	notice(tx, "A full rescan will be performed to calculate album sizes.")
-	return forceFullRescan(tx)
+
+update album set size = ifnull((
+select sum(f.size)
+from media_file f
+where f.album_id = album.id
+), 0)
+where id not null;`)
+
+	return err
 }
 
 func Down20201010162350(tx *sql.Tx) error {

db/migration/20201012210022_add_artist_playlist_size.go

@@ -17,6 +17,13 @@ alter table artist
 create index if not exists artist_size
 	on artist(size);
 
+update artist set size = ifnull((
+   select sum(f.size)
+   from album f
+   where f.album_artist_id = artist.id
+), 0)
+where id not null;
+
 alter table playlist
 	add size integer default 0 not null;
 create index if not exists playlist_size
@@ -29,11 +36,7 @@ update playlist set size = ifnull((
     where pt.playlist_id = playlist.id
 ), 0);`)
 
-	if err != nil {
-		return err
-	}
-	notice(tx, "A full rescan will be performed to calculate artists (discographies) and playlists sizes.")
-	return forceFullRescan(tx)
+	return err
 }
 
 func Down20201012210022(tx *sql.Tx) error {

db/migration/migration.go

@@ -29,9 +29,12 @@ update media_file set updated_at = '0001-01-01';
 	return err
 }
 
-var once sync.Once
+var (
+	once        sync.Once
+	initialized bool
+)
 
-func isDBInitialized(tx *sql.Tx) (initialized bool) {
+func isDBInitialized(tx *sql.Tx) bool {
 	once.Do(func() {
 		rows, err := tx.Query("select count(*) from property where id=?", consts.InitialSetupFlagKey)
 		checkErr(err)