From a2b6bc9e5334e4357c10a5a6553486b2d9bd5e24 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 18 Jan 2022 18:10:00 +0900
Subject: [PATCH 1/2] Add benchmark coverage of variuos methods of reading
 properties from realm

---
 osu.Game.Benchmarks/BenchmarkRealmReads.cs | 139 +++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 osu.Game.Benchmarks/BenchmarkRealmReads.cs

diff --git a/osu.Game.Benchmarks/BenchmarkRealmReads.cs b/osu.Game.Benchmarks/BenchmarkRealmReads.cs
new file mode 100644
index 0000000000..5b5bdf595d
--- /dev/null
+++ b/osu.Game.Benchmarks/BenchmarkRealmReads.cs
@@ -0,0 +1,139 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using System.Threading;
+using BenchmarkDotNet.Attributes;
+using osu.Framework.Testing;
+using osu.Framework.Threading;
+using osu.Game.Beatmaps;
+using osu.Game.Database;
+using osu.Game.Rulesets.Osu;
+using osu.Game.Tests.Resources;
+
+namespace osu.Game.Benchmarks
+{
+    public class BenchmarkRealmReads : BenchmarkTest
+    {
+        private TemporaryNativeStorage storage;
+        private RealmContextFactory realmFactory;
+        private UpdateThread updateThread;
+
+        [Params(1, 100, 1000)]
+        public int ReadsPerFetch { get; set; }
+
+        public override void SetUp()
+        {
+            storage = new TemporaryNativeStorage("realm-benchmark");
+            storage.DeleteDirectory(string.Empty);
+
+            realmFactory = new RealmContextFactory(storage, "client");
+
+            using (var context = realmFactory.CreateContext())
+                context.Write(c => c.Add(TestResources.CreateTestBeatmapSetInfo(rulesets: new[] { new OsuRuleset().RulesetInfo })));
+
+            updateThread = new UpdateThread(() => { }, null);
+            updateThread.Start();
+        }
+
+        [Benchmark]
+        public void BenchmarkDirectPropertyRead()
+        {
+            using (var context = realmFactory.CreateContext())
+            {
+                var beatmapSet = context.All<BeatmapSetInfo>().First();
+
+                for (int i = 0; i < ReadsPerFetch; i++)
+                {
+                    string _ = beatmapSet.Beatmaps.First().Hash;
+                }
+            }
+        }
+
+        [Benchmark]
+        public void BenchmarkDirectPropertyReadUpdateThread()
+        {
+            var done = new ManualResetEventSlim();
+
+            updateThread.Scheduler.Add(() =>
+            {
+                try
+                {
+                    var beatmapSet = realmFactory.Context.All<BeatmapSetInfo>().First();
+
+                    for (int i = 0; i < ReadsPerFetch; i++)
+                    {
+                        string _ = beatmapSet.Beatmaps.First().Hash;
+                    }
+                }
+                finally
+                {
+                    done.Set();
+                }
+            });
+
+            done.Wait();
+        }
+
+        [Benchmark]
+        public void BenchmarkRealmLivePropertyRead()
+        {
+            using (var context = realmFactory.CreateContext())
+            {
+                var beatmapSet = context.All<BeatmapSetInfo>().First().ToLive(realmFactory);
+
+                for (int i = 0; i < ReadsPerFetch; i++)
+                {
+                    string _ = beatmapSet.PerformRead(b => b.Beatmaps.First().Hash);
+                }
+            }
+        }
+
+        [Benchmark]
+        public void BenchmarkRealmLivePropertyReadUpdateThread()
+        {
+            var done = new ManualResetEventSlim();
+
+            updateThread.Scheduler.Add(() =>
+            {
+                try
+                {
+                    var beatmapSet = realmFactory.Context.All<BeatmapSetInfo>().First().ToLive(realmFactory);
+
+                    for (int i = 0; i < ReadsPerFetch; i++)
+                    {
+                        string _ = beatmapSet.PerformRead(b => b.Beatmaps.First().Hash);
+                    }
+                }
+                finally
+                {
+                    done.Set();
+                }
+            });
+
+            done.Wait();
+        }
+
+        [Benchmark]
+        public void BenchmarkDetachedPropertyRead()
+        {
+            using (var context = realmFactory.CreateContext())
+            {
+                var beatmapSet = context.All<BeatmapSetInfo>().First().Detach();
+
+                for (int i = 0; i < ReadsPerFetch; i++)
+                {
+                    string _ = beatmapSet.Beatmaps.First().Hash;
+                }
+            }
+        }
+
+        [GlobalCleanup]
+        public void Cleanup()
+        {
+            realmFactory?.Dispose();
+            storage?.Dispose();
+            updateThread?.Exit();
+        }
+    }
+}

From 8ef50ff42dab85eaae680274ccd7d3b25a78de2f Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Mon, 17 Jan 2022 17:28:01 +0900
Subject: [PATCH 2/2] Add safety to ensure `RealmLiveUnmanaged` is not used
 with managed instances

---
 osu.Game/Database/RealmLiveUnmanaged.cs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/osu.Game/Database/RealmLiveUnmanaged.cs b/osu.Game/Database/RealmLiveUnmanaged.cs
index ea50ccc1ff..97f2faa656 100644
--- a/osu.Game/Database/RealmLiveUnmanaged.cs
+++ b/osu.Game/Database/RealmLiveUnmanaged.cs
@@ -21,6 +21,9 @@ namespace osu.Game.Database
         /// <param name="data">The realm data.</param>
         public RealmLiveUnmanaged(T data)
         {
+            if (data.IsManaged)
+                throw new InvalidOperationException($"Cannot use {nameof(RealmLiveUnmanaged<T>)} with managed instances");
+
             Value = data;
         }