From 6a2b178d2125dcf79750e12d45f0fa71da8c4284 Mon Sep 17 00:00:00 2001
From: Ahmed Yasin Koculu <koculu@gmail.com>
Date: Sun, 8 Sep 2024 00:27:22 +0200
Subject: [PATCH] Set NextOpIndex after loading BTree to remove skipped regions
 on op index.

---
 src/ZoneTree.UnitTests/OpIndexTests.cs        | 68 +++++++++++++++++--
 src/ZoneTree/Directory.Build.props            |  4 +-
 .../Segments/InMemory/MutableSegment.cs       |  3 +-
 3 files changed, 67 insertions(+), 8 deletions(-)

diff --git a/src/ZoneTree.UnitTests/OpIndexTests.cs b/src/ZoneTree.UnitTests/OpIndexTests.cs
index 4360abd..e941e7b 100644
--- a/src/ZoneTree.UnitTests/OpIndexTests.cs
+++ b/src/ZoneTree.UnitTests/OpIndexTests.cs
@@ -31,19 +31,77 @@ void CreateData()
             maintainer.WaitForBackgroundThreads();
         }
 
-        void ReloadData()
+        void ReloadData(int expectedIndex, bool drop = false)
         {
             using var zoneTree = new ZoneTreeFactory<int, int>()
                 .SetDataDirectory(dataPath)
                 .SetMutableSegmentMaxItemCount(100)
                 .Open();
 
-            var opIndex = zoneTree.Upsert(recordCount + 1, recordCount + 1);
-            Assert.That(opIndex, Is.EqualTo(recordCount + 1));
-            zoneTree.Maintenance.Drop();
+            var opIndex = zoneTree.Upsert(expectedIndex, expectedIndex);
+            Assert.That(opIndex, Is.EqualTo(expectedIndex));
+            if (drop)
+                zoneTree.Maintenance.Drop();
         }
+
         CreateData();
-        ReloadData();
+        ReloadData(recordCount + 1);
+        ReloadData(recordCount + 2);
+        ReloadData(recordCount + 3, true);
+
+        Assert.IsTrue(
+            opIndexes.Order().ToArray()
+            .SequenceEqual(Enumerable.Range(1, recordCount).Select(x => (long)x)));
+    }
+
+    [Test]
+    public void TestOpIndex2()
+    {
+        var dataPath = "data/TestOpIndex2";
+        if (Directory.Exists(dataPath))
+            Directory.Delete(dataPath, true);
+        var recordCount = 10_000;
+        var opIndexes = new ConcurrentBag<long>();
+        void CreateData()
+        {
+            using var zoneTree = new ZoneTreeFactory<int, int>()
+                .SetDataDirectory(dataPath)
+                .SetMutableSegmentMaxItemCount(100)
+                .OpenOrCreate();
+
+            using var maintainer = zoneTree.CreateMaintainer();
+            Parallel.For(0, recordCount, (i) =>
+            {
+                var opIndex = zoneTree.Upsert(i, i);
+                opIndexes.Add(opIndex);
+            });
+            maintainer.EvictToDisk();
+            maintainer.WaitForBackgroundThreads();
+        }
+
+        void ReloadData(int expectedIndex, bool drop = false)
+        {
+            using var zoneTree = new ZoneTreeFactory<int, int>()
+                .SetDataDirectory(dataPath)
+                .SetMutableSegmentMaxItemCount(100)
+                .Open();
+
+            var opIndex = zoneTree.Upsert(expectedIndex, expectedIndex);
+            Assert.That(opIndex, Is.EqualTo(expectedIndex));
+
+            using var maintainer = zoneTree.CreateMaintainer();
+            maintainer.EvictToDisk();
+            maintainer.WaitForBackgroundThreads();
+
+            if (drop)
+                zoneTree.Maintenance.Drop();
+        }
+
+        CreateData();
+        ReloadData(recordCount + 1);
+        ReloadData(recordCount + 2);
+        ReloadData(recordCount + 3, true);
+
         Assert.IsTrue(
             opIndexes.Order().ToArray()
             .SequenceEqual(Enumerable.Range(1, recordCount).Select(x => (long)x)));
diff --git a/src/ZoneTree/Directory.Build.props b/src/ZoneTree/Directory.Build.props
index 5b024ff..4017992 100644
--- a/src/ZoneTree/Directory.Build.props
+++ b/src/ZoneTree/Directory.Build.props
@@ -5,8 +5,8 @@
     <Authors>Ahmed Yasin Koculu</Authors>
     <PackageId>ZoneTree</PackageId>
     <Title>ZoneTree</Title>
-    <ProductVersion>1.8.1.0</ProductVersion>
-    <Version>1.8.1.0</Version>
+    <ProductVersion>1.8.2.0</ProductVersion>
+    <Version>1.8.2.0</Version>
     <Authors>Ahmed Yasin Koculu</Authors>
     <AssemblyTitle>ZoneTree</AssemblyTitle>
     <Description>ZoneTree is a persistent, high-performance, transactional, ACID-compliant ordered key-value database for NET. It can operate in memory or on local/cloud storage.</Description>
diff --git a/src/ZoneTree/Segments/InMemory/MutableSegment.cs b/src/ZoneTree/Segments/InMemory/MutableSegment.cs
index 748a650..87b82a7 100644
--- a/src/ZoneTree/Segments/InMemory/MutableSegment.cs
+++ b/src/ZoneTree/Segments/InMemory/MutableSegment.cs
@@ -82,7 +82,6 @@ public MutableSegment(
             null,
             Options.BTreeNodeSize,
             Options.BTreeLeafSize);
-        BTree.SetNextOpIndex(nextOpIndex);
 
         MarkValueDeleted = options.MarkValueDeleted;
         MutableSegmentMaxItemCount = options.MutableSegmentMaxItemCount;
@@ -96,6 +95,8 @@ public MutableSegment(
         {
             LoadLogEntries(keys, values);
         }
+        // set op index after loading entries.
+        BTree.SetNextOpIndex(nextOpIndex);
     }
 
     void LoadLogEntries(IReadOnlyList<TKey> keys, IReadOnlyList<TValue> values)