Optimized queries to iterate over artists/releases, when specifying a media library

src/libs/database/impl/Artist.cpp

@@ -196,10 +196,8 @@ namespace lms::db
 
         if (library.isValid())
         {
-            query.join("track t ON t.id = t_a_l.track_id");
+            // Faster than using joins
-            query.join("track_artist_link t_a_l ON t_a_l.artist_id = a.id");
+            query.where("EXISTS (SELECT 1 FROM track_artist_link t_a_l JOIN track t ON t.id = t_a_l.track_id WHERE t_a_l.artist_id = a.id AND t.media_library_id = ?)").bind(library);
-            query.where("t.media_library_id = ?").bind(library);
-            query.groupBy("a.id");
         }
 
         utils::forEachQueryResult(query, [&](const Artist::pointer& artist)

src/libs/database/impl/Release.cpp

@@ -294,9 +294,8 @@ namespace lms::db
 
         if (library.isValid())
         {
-            query.join("track t ON t.release_id = r.id");
+            // Faster than using joins
-            query.where("t.media_library_id = ?").bind(library);
+            query.where("EXISTS (SELECT 1 FROM track t WHERE t.release_id = r.id AND t.media_library_id = ?)").bind(library);
-            query.groupBy("r.id");
         }
 
         utils::forEachQueryResult(query, [&](const Release::pointer& release)