Fixed: Cleanup duplicate Series Metadata files in database on startup

src/NzbDrone.Core/Housekeeping/Housekeepers/CleanupDuplicateMetadataFiles.cs

@@ -0,0 +1,37 @@
+using NLog;
+using NzbDrone.Core.Datastore;
+
+namespace NzbDrone.Core.Housekeeping.Housekeepers
+{
+    public class CleanupDuplicateMetadataFiles : IHousekeepingTask
+    {
+        private readonly IDatabase _database;
+        private readonly Logger _logger;
+
+        public CleanupDuplicateMetadataFiles(IDatabase database, Logger logger)
+        {
+            _database = database;
+            _logger = logger;
+        }
+
+        public void Clean()
+        {
+            _logger.Debug("Running cleanup of duplicate metadata files");
+
+            DeleteDuplicateSeriesMetadata();
+        }
+
+        private void DeleteDuplicateSeriesMetadata()
+        {
+            var mapper = _database.GetDataMapper();
+
+            mapper.ExecuteNonQuery(@"DELETE FROM MetadataFiles
+                                     WHERE Id IN (
+                                         SELECT Id FROM MetadataFiles
+                                         WHERE Type = 1
+                                         GROUP BY SeriesId, Consumer
+                                         HAVING COUNT(SeriesId) > 1
+                                     )");
+        }
+    }
+}