perf: use System.Threading.Lock for .NET 9+

Replace lock(object)/Monitor with System.Threading.Lock
for .NET 9 and above to reduce lock overhead in
uncontended scenarios.

Benchmark results show improvements in lightweight
operations (Get/Exists/TTL) with no regression in
write-heavy paths.

Author: VAllens

Benchmark/Benchmark.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <OutputPath>..\Bin\Benchmark</OutputPath>
     <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
     <ImplicitUsings>enable</ImplicitUsings>

NewLife.NovaDb/Client/EmbeddedDatabase.cs

@@ -16,7 +16,11 @@ internal sealed class EmbeddedDatabase
     private readonly DbOptions _options;
     private readonly ConcurrentDictionary<String, KvStore> _kvStores = new(StringComparer.OrdinalIgnoreCase);
     private FluxEngine? _fluxEngine;
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _fluxLock = new();
+#else
     private readonly Object _fluxLock = new();
+#endif
 
     /// <summary>数据库路径</summary>
     public String DbPath => _dbPath;

NewLife.NovaDb/Cluster/FailoverManager.cs

@@ -12,7 +12,11 @@ namespace NewLife.NovaDb.Cluster;
 public class FailoverManager
 {
     private readonly ReplicationManager _replication;
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
 
     /// <summary>允许切换的最大复制延迟（LSN 差值）。超过此值拒绝切换，避免数据丢失。默认 100</summary>
     public UInt64 MaxAllowedLag { get; set; } = 100;

NewLife.NovaDb/Cluster/ReplicaClient.cs

@@ -20,7 +20,11 @@ public class ReplicaClient : IDisposable
     private UInt64 _lastAppliedLsn;
     private readonly List<WalRecord> _appliedRecords = [];
     private readonly Action<UInt64, Byte[]>? _applyCallback;
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
     private Boolean _isConnected;
     private Boolean _disposed;
 

NewLife.NovaDb/Cluster/ReplicationManager.cs

@@ -20,7 +20,11 @@ public class ReplicationManager : IDisposable
     private readonly Dictionary<String, NodeInfo> _slaves = [];
     private readonly Dictionary<String, UInt64> _slavePositions = [];
     private readonly Dictionary<String, ApiClient> _slaveClients = [];
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
     private Boolean _disposed;
 
     private readonly List<WalRecord> _replicationBuffer = [];

NewLife.NovaDb/Core/SlowQueryLog.cs

@@ -39,7 +39,11 @@ public IReadOnlyList<SlowQueryEntry> RecentEntries
     #region 字段
     private Int64 _totalCount;
     private readonly LinkedList<SlowQueryEntry> _entries = new();
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
     #endregion
 
     #region 日志

NewLife.NovaDb/Engine/ColdIndexDirectory.cs

@@ -20,7 +20,11 @@ public class ColdIndexDirectory
 {
     private readonly Int32 _anchorInterval;
     private readonly List<ColdDirectoryEntry> _anchors = [];
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
 
     /// <summary>锚点间隔（行数），默认 1000 行一个锚点</summary>
     public Int32 AnchorInterval => _anchorInterval;

NewLife.NovaDb/Engine/Flux/ConsumerGroup.cs

@@ -26,7 +26,11 @@ public class ConsumerGroup
     public MessageId? LastDeliveredId { get; set; }
 
     private readonly Dictionary<String, PendingEntry> _pendingEntries = [];
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
 
     /// <summary>创建消费组</summary>
     /// <param name="name">消费组名称</param>

NewLife.NovaDb/Engine/Flux/FluxEngine.cs

@@ -8,7 +8,11 @@ public partial class FluxEngine : IDisposable
     private readonly String _basePath;
     private readonly DbOptions _options;
     private readonly SortedDictionary<String, List<FluxEntry>> _partitions = new(StringComparer.Ordinal);
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
     private Boolean _disposed;
 
     /// <summary>创建 FluxEngine 实例</summary>

NewLife.NovaDb/Engine/HotIndexManager.cs

@@ -48,7 +48,11 @@ public class HotIndexManager
 {
     private readonly HotSegmentConfig _config;
     private readonly SkipList<ComparableObject, IndexSegment> _hotSegments;
+#if NET9_0_OR_GREATER
+    private readonly System.Threading.Lock _lock = new();
+#else
     private readonly Object _lock = new();
+#endif
     private DateTime _lastHeatCheck = DateTime.UtcNow;
 
     /// <summary>配置</summary>