Fixed duplicate UpdateHistory items

src/NzbDrone.Core/Datastore/Migration/146_cleanup_duplicates_updatehistory.cs

@@ -0,0 +1,59 @@
+using System.Collections.Generic;
+using System.Data;
+using System.Linq;
+using FluentMigrator;
+using NzbDrone.Common.Extensions;
+using NzbDrone.Core.Datastore.Migration.Framework;
+
+namespace NzbDrone.Core.Datastore.Migration
+{
+    [Migration(146)]
+    public class cleanup_duplicates_updatehistory : NzbDroneMigrationBase
+    {
+        protected override void LogDbUpgrade()
+        {
+            Execute.WithConnection(CleanupUpdateHistory);
+        }
+
+        private void CleanupUpdateHistory(IDbConnection conn, IDbTransaction tran)
+        {
+            var toDelete = new List<int>();
+
+            using (var cmdQuery = conn.CreateCommand())
+            {
+                cmdQuery.Transaction = tran;
+                cmdQuery.CommandText = "SELECT Id, Version FROM UpdateHistory WHERE EventType = 2 ORDER BY Date";
+
+                var lastVersion = string.Empty;
+                using (var reader = cmdQuery.ExecuteReader())
+                {
+                    while (reader.Read())
+                    {
+                        var id = reader.GetInt32(0);
+                        var version = reader.GetString(1);
+
+                        if (lastVersion == version)
+                        {
+                            toDelete.Add(id);
+                        }
+
+                        lastVersion = version;
+                    }
+                }
+            }
+
+            if (toDelete.Any())
+            {
+                using (var cmdDelete = conn.CreateCommand())
+                {
+                    var ids = toDelete.Select(v => v.ToString()).Join(", ");
+
+                    cmdDelete.Transaction = tran;
+                    cmdDelete.CommandText = $"DELETE FROM UpdateHistory WHERE Id IN ({ids})";
+
+                    cmdDelete.ExecuteNonQuery();
+                }
+            }
+        }
+    }
+}

src/NzbDrone.Core/Update/History/UpdateHistoryRepository.cs

@@ -26,7 +26,7 @@ namespace NzbDrone.Core.Update.History
         public UpdateHistory LastInstalled()
         {
             var history = Query.Where(v => v.EventType == UpdateHistoryEventType.Installed)
-                               .OrderBy(v => v.Date)
+                               .OrderByDescending(v => v.Date)
                                .Take(1)
                                .FirstOrDefault();
 
@@ -36,7 +36,7 @@ namespace NzbDrone.Core.Update.History
         public UpdateHistory PreviouslyInstalled()
         {
             var history = Query.Where(v => v.EventType == UpdateHistoryEventType.Installed)
-                               .OrderBy(v => v.Date)
+                               .OrderByDescending(v => v.Date)
                                .Skip(1)
                                .Take(1)
                                .FirstOrDefault();