diff --git a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationManager.cs b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationManager.cs
index d012d786b10..cc3082a097c 100644
--- a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationManager.cs
+++ b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationManager.cs
@@ -25,7 +25,7 @@ public interface IOperationManager
     /// Returns <c>true</c> if the <paramref name="request"/>
     /// was accepted and registered for execution.
     /// </returns>
-    bool Enqueue(string sessionId, GraphQLRequest request);
+    bool Start(string sessionId, GraphQLRequest request);
 
     /// <summary>
     /// Completes a request that was previously enqueued with the operation manager.
diff --git a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationSession.cs b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationSession.cs
index 24de59f3e6c..a308760be2c 100644
--- a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationSession.cs
+++ b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/IOperationSession.cs
@@ -9,11 +9,6 @@ namespace HotChocolate.AspNetCore.Subscriptions;
 /// </summary>
 public interface IOperationSession : IDisposable
 {
-    /// <summary>
-    /// An event that indicates that the underlying subscription has completed.
-    /// </summary>
-    event EventHandler? Completed;
-
     /// <summary>
     /// Gets the subscription id that the client has provided.
     /// </summary>
@@ -27,7 +22,22 @@ public interface IOperationSession : IDisposable
     /// <summary>
     /// Starts executing the operation.
     /// </summary>
-    /// <param name="request">The graphql request.</param>
-    /// <param name="cancellationToken">The cancellation token.</param>
-    void BeginExecute(GraphQLRequest request, CancellationToken cancellationToken);
+    /// <param name="request">
+    /// The graphql request.
+    /// </param>
+    /// <param name="completion">
+    /// The completion handler that will be called when the operation is completed.
+    /// </param>
+    /// <param name="cancellationToken">
+    /// The cancellation token.
+    /// </param>
+    void BeginExecute(
+        GraphQLRequest request,
+        IOperationSessionCompletionHandler completion,
+        CancellationToken cancellationToken);
+}
+
+public interface IOperationSessionCompletionHandler
+{
+    void Complete(IOperationSession session);
 }
diff --git a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationManager.cs b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationManager.cs
index 9196b135c58..31025b26c68 100644
--- a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationManager.cs
+++ b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationManager.cs
@@ -1,4 +1,5 @@
 using System.Collections;
+using System.Collections.Concurrent;
 using HotChocolate.Language;
 using Microsoft.Extensions.DependencyInjection;
 using static HotChocolate.AspNetCore.Properties.AspNetCoreResources;
@@ -12,8 +13,8 @@ namespace HotChocolate.AspNetCore.Subscriptions;
 /// </summary>
 public sealed class OperationManager : IOperationManager
 {
-    private readonly ReaderWriterLockSlim _lock = new();
-    private readonly Dictionary<string, IOperationSession> _subs = new();
+    private readonly ConcurrentDictionary<string, IOperationSession> _subs = new();
+    private readonly OperationSessionCompletionHandler _completion;
     private readonly CancellationTokenSource _cts;
     private readonly CancellationToken _cancellationToken;
     private readonly ISocketSession _socketSession;
@@ -35,6 +36,7 @@ public OperationManager(
         _errorHandler = executor.Services.GetRequiredService<IErrorHandler>();
         _cts = new CancellationTokenSource();
         _cancellationToken = _cts.Token;
+        _completion = new OperationSessionCompletionHandler(_subs);
     }
 
     internal OperationManager(
@@ -50,10 +52,11 @@ internal OperationManager(
         _errorHandler = executor.Services.GetRequiredService<IErrorHandler>();
         _cts = new CancellationTokenSource();
         _cancellationToken = _cts.Token;
+        _completion = new OperationSessionCompletionHandler(_subs);
     }
 
     /// <inheritdoc />
-    public bool Enqueue(string sessionId, GraphQLRequest request)
+    public bool Start(string sessionId, GraphQLRequest request)
     {
         if (string.IsNullOrEmpty(sessionId))
         {
@@ -72,30 +75,18 @@ public bool Enqueue(string sessionId, GraphQLRequest request)
             throw new ObjectDisposedException(nameof(OperationManager));
         }
 
-        IOperationSession? session = null;
-        _lock.EnterWriteLock();
+        var context = new StartSessionContext(
+            _createSession,
+            _completion,
+            request,
+            _cancellationToken);
 
-        try
-        {
-            if(!_subs.ContainsKey(sessionId))
-            {
-                session = _createSession(sessionId);
-                _subs.Add(sessionId, session);
-            }
-        }
-        finally
-        {
-            _lock.ExitWriteLock();
-        }
+        _subs.GetOrAdd(
+            sessionId,
+            static (key, ctx) => ctx.CreateSession(key),
+            context);
 
-        if (session is not null)
-        {
-            session.Completed += (_, _) => Complete(sessionId);
-            session.BeginExecute(request, _cancellationToken);
-            return true;
-        }
-
-        return false;
+        return context.IsNewSession;
     }
 
     /// <inheritdoc />
@@ -113,20 +104,10 @@ public bool Complete(string sessionId)
             throw new ObjectDisposedException(nameof(OperationManager));
         }
 
-        _lock.EnterWriteLock();
-
-        try
-        {
-            if (_subs.TryGetValue(sessionId, out var session))
-            {
-                _subs.Remove(sessionId);
-                session.Dispose();
-                return true;
-            }
-        }
-        finally
+        if(_subs.TryRemove(sessionId, out var session))
         {
-            _lock.ExitWriteLock();
+            session.Dispose();
+            return true;
         }
 
         return false;
@@ -149,24 +130,37 @@ public void Dispose()
 
     /// <inheritdoc />
     public IEnumerator<IOperationSession> GetEnumerator()
+        => _subs.Values.GetEnumerator();
+
+    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+    private sealed class StartSessionContext(
+        Func<string, IOperationSession> createSession,
+        IOperationSessionCompletionHandler completion,
+        GraphQLRequest request,
+        CancellationToken cancellationToken)
     {
-        _lock.EnterReadLock();
-        IOperationSession[] items;
+        public bool IsNewSession { get; private set; }
 
-        try
-        {
-            items = _subs.Values.ToArray();
-        }
-        finally
+        public IOperationSession CreateSession(string sessionId)
         {
-            _lock.ExitReadLock();
+            IsNewSession = true;
+            var session = createSession(sessionId);
+            session.BeginExecute(request, completion, cancellationToken);
+            return session;
         }
+    }
 
-        foreach (var session in items)
+    private sealed class OperationSessionCompletionHandler(
+        ConcurrentDictionary<string, IOperationSession> subs)
+        : IOperationSessionCompletionHandler
+    {
+        public void Complete(IOperationSession session)
         {
-            yield return session;
+            if (subs.TryRemove(session.Id, out _))
+            {
+                session.Dispose();
+            }
         }
     }
-
-    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
 }
diff --git a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationSession.cs b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationSession.cs
index 2ff5521dce7..495db0e8534 100644
--- a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationSession.cs
+++ b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/OperationSession.cs
@@ -13,8 +13,6 @@ internal sealed class OperationSession : IOperationSession
     private readonly IRequestExecutor _executor;
     private bool _disposed;
 
-    public event EventHandler? Completed;
-
     public OperationSession(
         ISocketSession session,
         ISocketSessionInterceptor interceptor,
@@ -34,10 +32,16 @@ public OperationSession(
 
     public bool IsCompleted { get; private set; }
 
-    public void BeginExecute(GraphQLRequest request, CancellationToken cancellationToken)
-        => SendResultsAsync(request, cancellationToken).FireAndForget();
+    public void BeginExecute(
+        GraphQLRequest request,
+        IOperationSessionCompletionHandler completion,
+        CancellationToken cancellationToken)
+        => SendResultsAsync(request, completion, cancellationToken).FireAndForget();
 
-    private async Task SendResultsAsync(GraphQLRequest request, CancellationToken cancellationToken)
+    private async Task SendResultsAsync(
+        GraphQLRequest request,
+        IOperationSessionCompletionHandler completion,
+        CancellationToken cancellationToken)
     {
         using var cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, _ct);
         var ct = cts.Token;
@@ -51,32 +55,28 @@ private async Task SendResultsAsync(GraphQLRequest request, CancellationToken ca
 
             switch (result)
             {
-                case IOperationResult queryResult:
-                    if (queryResult.Data is null && queryResult.Errors is { Count: > 0, })
+                case IOperationResult singleResult:
+                    if (singleResult.Data is null && singleResult.Errors is { Count: > 0, })
                     {
-                        await _session.Protocol.SendErrorMessageAsync(
-                            _session,
-                            Id,
-                            queryResult.Errors,
-                            ct);
+                        await _session.Protocol.SendErrorMessageAsync(_session, Id, singleResult.Errors, ct).ConfigureAwait(false);
                     }
                     else
                     {
-                        await SendResultMessageAsync(queryResult, ct);
+                        await SendResultMessageAsync(singleResult, ct).ConfigureAwait(false);
                     }
                     break;
 
                 case IResponseStream responseStream:
-                    await foreach (var item in responseStream.ReadResultsAsync().WithCancellation(ct))
+                    await foreach (var item in responseStream.ReadResultsAsync().WithCancellation(ct).ConfigureAwait(false))
                     {
                         try
                         {
                             // use original cancellation token here to keep the websocket open for other streams.
-                            await SendResultMessageAsync(item, cancellationToken);
+                            await SendResultMessageAsync(item, cancellationToken).ConfigureAwait(false);
                         }
                         finally
                         {
-                            await item.DisposeAsync();
+                            await item.DisposeAsync().ConfigureAwait(false);
                         }
                     }
                     break;
@@ -94,7 +94,7 @@ await _session.Protocol.SendErrorMessageAsync(
         }
         catch (OperationCanceledException) when (ct.IsCancellationRequested)
         {
-            // the operation was cancelled so we do nothings
+            // the operation was cancelled so we do nothing
         }
         catch (Exception ex)
         {
@@ -121,7 +121,8 @@ await _session.Protocol.SendErrorMessageAsync(
             }
 
             // signal that the subscription is completed.
-            Complete();
+            completion.Complete(this);
+            IsCompleted = true;
         }
     }
 
@@ -180,7 +181,7 @@ private async Task TrySendErrorMessageAsync(Exception exception, CancellationTok
                 var errors =
                     error is AggregateError aggregateError
                         ? aggregateError.Errors
-                        : new[] { error, };
+                        : [error];
 
                 await _session.Protocol.SendErrorMessageAsync(_session, Id, errors, ct);
             }
@@ -192,19 +193,6 @@ error is AggregateError aggregateError
         }
     }
 
-    private void Complete()
-    {
-        try
-        {
-            IsCompleted = true;
-            Completed?.Invoke(this, EventArgs.Empty);
-        }
-        catch
-        {
-            // we ignore any error that might happen on invoking complete.
-        }
-    }
-
     public void Dispose()
     {
         if (!_disposed)
diff --git a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/Apollo/ApolloSubscriptionProtocolHandler.cs b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/Apollo/ApolloSubscriptionProtocolHandler.cs
index 07f68a04f2a..6385761963f 100644
--- a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/Apollo/ApolloSubscriptionProtocolHandler.cs
+++ b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/Apollo/ApolloSubscriptionProtocolHandler.cs
@@ -141,7 +141,7 @@ await connection.CloseAsync(
                     return;
                 }
 
-                if (!session.Operations.Enqueue(dataStartMessage.Id, dataStartMessage.Payload))
+                if (!session.Operations.Start(dataStartMessage.Id, dataStartMessage.Payload))
                 {
                     await connection.CloseAsync(
                         Apollo_OnReceive_SubscriptionIdNotUnique,
diff --git a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/GraphQLOverWebSocket/GraphQLOverWebSocketProtocolHandler.cs b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/GraphQLOverWebSocket/GraphQLOverWebSocketProtocolHandler.cs
index 57e1754a76f..70bc9ffae40 100644
--- a/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/GraphQLOverWebSocket/GraphQLOverWebSocketProtocolHandler.cs
+++ b/src/HotChocolate/AspNetCore/src/AspNetCore/Subscriptions/Protocols/GraphQLOverWebSocket/GraphQLOverWebSocketProtocolHandler.cs
@@ -142,7 +142,7 @@ await SendConnectionAcceptMessage(
                     return;
                 }
 
-                if (!session.Operations.Enqueue(subscribeMessage.Id, subscribeMessage.Payload))
+                if (!session.Operations.Start(subscribeMessage.Id, subscribeMessage.Payload))
                 {
                     await connection.CloseSubscriptionIdNotUniqueAsync(cancellationToken);
                     return;
diff --git a/src/HotChocolate/AspNetCore/test/AspNetCore.Tests/Subscriptions/OperationManagerTests.cs b/src/HotChocolate/AspNetCore/test/AspNetCore.Tests/Subscriptions/OperationManagerTests.cs
index ca999527f88..12111bc6903 100644
--- a/src/HotChocolate/AspNetCore/test/AspNetCore.Tests/Subscriptions/OperationManagerTests.cs
+++ b/src/HotChocolate/AspNetCore/test/AspNetCore.Tests/Subscriptions/OperationManagerTests.cs
@@ -25,7 +25,7 @@ public async Task Enqueue_SessionId_Is_Null()
         var subscriptions = new OperationManager(session.Object, interceptor.Object, executor);
 
         // act
-        void Action() => subscriptions.Enqueue(null!, new GraphQLRequest(null, queryId: "123"));
+        void Action() => subscriptions.Start(null!, new GraphQLRequest(null, queryId: "123"));
 
         // assert
         Assert.Equal(
@@ -48,7 +48,7 @@ public async Task Enqueue_SessionId_Is_Empty()
         var subscriptions = new OperationManager(session.Object, interceptor.Object, executor);
 
         // act
-        void Action() => subscriptions.Enqueue("", new GraphQLRequest(null, queryId: "123"));
+        void Action() => subscriptions.Start("", new GraphQLRequest(null, queryId: "123"));
 
         // assert
         Assert.Equal(
@@ -71,7 +71,7 @@ public async Task Enqueue_Request_Is_Null()
         var subscriptions = new OperationManager(session.Object, interceptor.Object, executor);
 
         // act
-        void Action() => subscriptions.Enqueue("abc", null!);
+        void Action() => subscriptions.Start("abc", null!);
 
         // assert
         Assert.Equal(
@@ -106,7 +106,7 @@ public async Task Enqueue_On_Disposed_Manager()
         subscriptions.Dispose();
 
         // act
-        void Fail() => subscriptions.Enqueue("abc", request);
+        void Fail() => subscriptions.Start("abc", request);
 
         // assert
         Assert.Throws<ObjectDisposedException>(Fail);
@@ -138,7 +138,7 @@ public async Task Enqueue_Request()
         var request = new GraphQLRequest(query);
 
         // act
-        var success = subscriptions.Enqueue("abc", request);
+        var success = subscriptions.Start("abc", request);
         var registered = subscriptions.ToArray();
 
         // assert
@@ -170,11 +170,11 @@ public async Task Enqueue_Request_With_Non_Unique_Id()
         var query = Utf8GraphQLParser.Parse(
             "subscription { onReview(episode: NEW_HOPE) { stars } }");
         var request = new GraphQLRequest(query);
-        var success1 = subscriptions.Enqueue("abc", request);
+        var success1 = subscriptions.Start("abc", request);
         var registered1 = subscriptions.ToArray();
 
         // act
-        var success2 = subscriptions.Enqueue("abc", request);
+        var success2 = subscriptions.Start("abc", request);
         var registered2 = subscriptions.ToArray();
 
         // assert
@@ -208,7 +208,7 @@ public async Task Complete_Request()
         var query = Utf8GraphQLParser.Parse(
             "subscription { onReview(episode: NEW_HOPE) { stars } }");
         var request = new GraphQLRequest(query);
-        var success1 = subscriptions.Enqueue("abc", request);
+        var success1 = subscriptions.Start("abc", request);
         var registered1 = subscriptions.ToArray();
 
         // act
@@ -322,7 +322,7 @@ public async Task Dispose_OperationManager()
         var query = Utf8GraphQLParser.Parse(
             "subscription { onReview(episode: NEW_HOPE) { stars } }");
         var request = new GraphQLRequest(query);
-        var success = subscriptions.Enqueue("abc", request);
+        var success = subscriptions.Start("abc", request);
         Assert.True(success);
 
         // act
diff --git a/src/HotChocolate/Core/src/Execution/Processing/ISubscription.cs b/src/HotChocolate/Core/src/Execution/Processing/ISubscription.cs
index f4a4c168d29..da033aa6cce 100644
--- a/src/HotChocolate/Core/src/Execution/Processing/ISubscription.cs
+++ b/src/HotChocolate/Core/src/Execution/Processing/ISubscription.cs
@@ -11,7 +11,12 @@ public interface ISubscription
     ulong Id { get; }
 
     /// <summary>
-    /// The compiled subscription operation.
+    /// Gets the compiled subscription operation.
     /// </summary>
     IOperation Operation { get; }
+
+    /// <summary>
+    /// Gets the global request state.
+    /// </summary>
+    IDictionary<string, object?> ContextData { get; }
 }
diff --git a/src/HotChocolate/Core/src/Execution/Processing/SubscriptionExecutor.Subscription.cs b/src/HotChocolate/Core/src/Execution/Processing/SubscriptionExecutor.Subscription.cs
index 96dd8adead0..6bf0b0e5e8e 100644
--- a/src/HotChocolate/Core/src/Execution/Processing/SubscriptionExecutor.Subscription.cs
+++ b/src/HotChocolate/Core/src/Execution/Processing/SubscriptionExecutor.Subscription.cs
@@ -118,6 +118,9 @@ public IAsyncEnumerable<IOperationResult> ExecuteAsync()
         /// <inheritdoc />
         public IOperation Operation => _requestContext.Operation!;
 
+        /// <inheritdoc />
+        public IDictionary<string, object?> ContextData => _requestContext.ContextData;
+
         public async ValueTask DisposeAsync()
         {
             if (!_disposed)