Use thread-safe random number generator.

src/Playground/Benchmark/OldTests.cs

@@ -125,7 +125,7 @@ public static void ShowBottomSegments(WriteAheadLogMode mode, int count)
         var iterate = false;
         if (iterate)
         {
-            var random = new Random();
+            var random = Random.Shared;
             Parallel.For(0, 750000, (i) =>
             {
                 var key = random.Next(0, 999_999_999);

src/Playground/DeadlockFinder.cs

@@ -20,7 +20,7 @@ void TreeLoop(int taskNo)
             const int upsertLogFrequency = 1_000_000;
             const int iterationLogFrequency = 10_000_000;
             const int iterationYieldFrequency = 1000;
-            var rand = new Random();
+            var rand = Random.Shared;
 
             void resetTree()
             {

src/ZoneTree.UnitTests/AtomicUpdateTests.cs

@@ -29,7 +29,7 @@ public void IntIntAtomicIncrement(WriteAheadLogMode walMode)
         }
         data.Maintenance.MoveMutableSegmentForward();
         data.Maintenance.StartMergeOperation().Join();
-        var random = new Random();
+        var random = Random.Shared;
         var off = -1;
         Parallel.For(0, 1001, (x) =>
         {
@@ -100,7 +100,7 @@ public void IntIntAtomicIncrementForBTree(WriteAheadLogMode walMode)
         {
             data.Upsert(i, i + i);
         }
-        var random = new Random();
+        var random = Random.Shared;
         var off = -1;
         Parallel.For(0, 1001, (x) =>
         {
@@ -166,7 +166,7 @@ public void IntIntMutableSegmentOnlyAtomicIncrement(WriteAheadLogMode walMode)
         {
             data.Upsert(i, i + i);
         }
-        var random = new Random();
+        var random = Random.Shared;
         var off = -1;
         Parallel.For(0, 1001, (x) =>
         {
@@ -228,7 +228,7 @@ public void IntIntMutableSegmentSeveralUpserts(WriteAheadLogMode walMode)
             .ConfigureWriteAheadLogOptions(x => x.WriteAheadLogMode = walMode)
             .OpenOrCreate();
         var n = 1000;
-        var random = new Random();
+        var random = Random.Shared;
         Parallel.For(0, 1000, (x) =>
         {
             try

src/ZoneTree.UnitTests/ExceptionlessTransactionTests.cs

@@ -82,7 +82,7 @@ public async Task TransactionWithFluentAPI(int compactionThreshold)
 
         zoneTree.Maintenance.TransactionLog.CompactionThreshold = compactionThreshold;
 
-        var random = new Random();
+        var random = Random.Shared;
         await Parallel.ForEachAsync(Enumerable.Range(0, 1000), async (x, cancel) =>
         {
             using var transaction =

src/ZoneTree.UnitTests/IteratorTests.cs

@@ -240,7 +240,7 @@ public void IntIntIteratorParallelInserts()
         if (Directory.Exists(dataPath))
             Directory.Delete(dataPath, true);
 
-        var random = new Random();
+        var random = Random.Shared;
         var insertCount = 100000;
         var iteratorCount = 1000;
 
@@ -289,7 +289,7 @@ public void IntIntReverseIteratorParallelInserts(bool reverse)
         if (Directory.Exists(dataPath))
             Directory.Delete(dataPath, true);
 
-        var random = new Random();
+        var random = Random.Shared;
         var insertCount = 1000000;
         var iteratorCount = 1000;
 
@@ -352,7 +352,7 @@ public void IntIntSnapshotIteratorParallelInserts()
         if (Directory.Exists(dataPath))
             Directory.Delete(dataPath, true);
 
-        var random = new Random();
+        var random = Random.Shared;
         var insertCount = 100000;
         var iteratorCount = 1000;
 
@@ -512,7 +512,7 @@ public void SeekIteratorsAfterMerge(
         if (merge)
             zoneTree.Maintenance.StartMergeOperation()?.Join();
 
-        var random = new Random();
+        var random = Random.Shared;
         DoPrefixSearch(zoneTree, list, random);
         zoneTree.Maintenance.DiskSegment.InitSparseArray(100);
         DoPrefixSearch(zoneTree, list, random);
@@ -604,7 +604,7 @@ public void SeekIteratorsAfterMergeReload(
                     x.MaximumRecordCount = maximumRecordCount;
             })
             .Open();
-        var random = new Random();
+        var random = Random.Shared;
         DoPrefixSearch(zoneTree, list, random);
         zoneTree.Maintenance.DiskSegment.InitSparseArray(100);
         DoPrefixSearch(zoneTree, list, random);

src/ZoneTree.UnitTests/SafeBplusTreeTests.cs

@@ -22,13 +22,13 @@ public void BTreeIteration(BTreeLockMode lockMode)
             tree.TryInsert(i, i + i, out _);
 
         var iterator = new BTreeSeekableIterator<int, int>(tree);
-        var j = 0; 
+        var j = 0;
         while (iterator.Next())
         {
             Assert.That(iterator.CurrentKey, Is.EqualTo(j));
             Assert.That(iterator.CurrentValue, Is.EqualTo(j + j));
             ++j;
-        } 
+        }
 
         iterator.SeekEnd();
         j = n - 1;
@@ -92,7 +92,7 @@ public void BTreeLowerOrEqualBound(BTreeLockMode lockMode)
             Assert.That(GetLastNodeSmallerOrEqual(iterator, 4), Is.EqualTo(3));
             Assert.That(GetLastNodeSmallerOrEqual(iterator, 3), Is.EqualTo(3));
             Assert.Throws<IndexOutOfRangeException>(
-                () => GetLastNodeSmallerOrEqual(iterator ,- 1));
+                () => GetLastNodeSmallerOrEqual(iterator, -1));
             Assert.That(GetLastNodeSmallerOrEqual(iterator, 10), Is.EqualTo(9));
             Assert.That(GetLastNodeSmallerOrEqual(iterator, 9), Is.EqualTo(9));
             Assert.That(GetLastNodeSmallerOrEqual(iterator, 1), Is.EqualTo(1));
@@ -135,7 +135,7 @@ int GetFirstNodeGreaterOrEqual(BTreeSeekableIterator<int, int> iterator, int key
     [TestCase(BTreeLockMode.NodeLevelMonitor)]
     public void BTreeIteratorParallelInserts(BTreeLockMode lockMode)
     {
-        var random = new Random();
+        var random = Random.Shared;
         var insertCount = 100000;
         var iteratorCount = 1000;
 
@@ -190,7 +190,7 @@ public void BTreeIteratorParallelInserts(BTreeLockMode lockMode)
     [TestCase(BTreeLockMode.NodeLevelMonitor)]
     public void BTreeReverseIteratorParallelInserts(BTreeLockMode lockMode)
     {
-        var random = new Random();
+        var random = Random.Shared;
         var insertCount = 100000;
         var iteratorCount = 1550;
 
@@ -203,7 +203,7 @@ public void BTreeReverseIteratorParallelInserts(BTreeLockMode lockMode)
             {
                 var key = random.Next();
                 tree.AddOrUpdate(key,
-                    AddOrUpdateResult  (ref int x) =>
+                    AddOrUpdateResult (ref int x) =>
                     {
                         x = key + key;
                         return AddOrUpdateResult.ADDED;
@@ -253,7 +253,7 @@ public void BTreeReverseIteratorParallelInserts(BTreeLockMode lockMode)
     [TestCase(BTreeLockMode.NodeLevelMonitor)]
     public void IntIntDuplicateRecords(BTreeLockMode lockMode)
     {
-        var random = new Random();
+        var random = Random.Shared;
         var insertCount = 1000000;
         var iteratorCount = 1000;
 
@@ -297,7 +297,7 @@ public void IntIntDuplicateRecords(BTreeLockMode lockMode)
     [TestCase(BTreeLockMode.NodeLevelMonitor)]
     public void IntIntDuplicateReverseRecords(BTreeLockMode lockMode)
     {
-        var random = new Random();
+        var random = Random.Shared;
         var insertCount = 1000000;
         var iteratorCount = 1000;
 

src/ZoneTree/Segments/MultiPart/MultiPartDiskSegmentCreator.cs

@@ -34,7 +34,7 @@ public sealed class MultiPartDiskSegmentCreator<TKey, TValue> : IDiskSegmentCrea
 
     readonly List<TValue> PartValues = new();
 
-    readonly Random Random = new();
+    readonly Random Random = Random.Shared;
 
     TKey LastAppendedKey;