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fix: race condition on inflight messages #249

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Merged
merged 3 commits into from
Jan 15, 2025
Merged

fix: race condition on inflight messages #249

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ed746a4
fix: race condition on _inFlightMessages
KirillKurdyukov Jan 15, 2025
37c57be
fix maybe flap test with SessionBusy
KirillKurdyukov Jan 15, 2025
38e57bd
fix flap tests in writer
KirillKurdyukov Jan 15, 2025
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2 changes: 2 additions & 0 deletions src/Ydb.Sdk/src/Services/Topic/TopicSession.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@ internal abstract class TopicSession<TFromClient, TFromServer> : IDisposable

private int _isActive = 1;

public bool IsActive => Volatile.Read(ref _isActive) == 1;

protected TopicSession(
IBidirectionalStream<TFromClient, TFromServer> stream,
ILogger logger,
Expand Down
94 changes: 62 additions & 32 deletions src/Ydb.Sdk/src/Services/Topic/Writer/Writer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@ internal class Writer<TValue> : IWriter<TValue>
private readonly ConcurrentQueue<MessageSending> _toSendBuffer = new();
private readonly ConcurrentQueue<MessageSending> _inFlightMessages = new();
private readonly CancellationTokenSource _disposeCts = new();
private readonly SemaphoreSlim _clearInFlightMessagesSemaphoreSlim = new(1);

private volatile TaskCompletionSource _tcsWakeUp = new();
private volatile TaskCompletionSource _tcsBufferAvailableEvent = new();
Expand Down Expand Up @@ -161,7 +162,18 @@ private async void StartWriteWorker()
continue;
}

await _session.Write(_toSendBuffer);
await _clearInFlightMessagesSemaphoreSlim.WaitAsync(_disposeCts.Token);
try
{
if (_session.IsActive)
{
await _session.Write(_toSendBuffer);
}
}
finally
{
_clearInFlightMessagesSemaphoreSlim.Release();
}
}
}
catch (OperationCanceledException)
Expand Down Expand Up @@ -255,54 +267,66 @@ private async Task Initialize()
return;
}

var copyInFlightMessages = new ConcurrentQueue<MessageSending>();
var lastSeqNo = initResponse.LastSeqNo;
while (_inFlightMessages.TryDequeue(out var sendData))
await _clearInFlightMessagesSemaphoreSlim.WaitAsync(_disposeCts.Token);
try
{
if (lastSeqNo >= sendData.MessageData.SeqNo)
var copyInFlightMessages = new ConcurrentQueue<MessageSending>();
var lastSeqNo = initResponse.LastSeqNo;
while (_inFlightMessages.TryDequeue(out var sendData))
{
_logger.LogWarning(
"Message[SeqNo={SeqNo}] has been skipped because its sequence number " +
"is less than or equal to the last processed server's SeqNo[{LastSeqNo}]",
sendData.MessageData.SeqNo, lastSeqNo);
if (lastSeqNo >= sendData.MessageData.SeqNo)
{
_logger.LogWarning(
"Message[SeqNo={SeqNo}] has been skipped because its sequence number " +
"is less than or equal to the last processed server's SeqNo[{LastSeqNo}]",
sendData.MessageData.SeqNo, lastSeqNo);

sendData.Tcs.TrySetResult(WriteResult.Skipped);
sendData.Tcs.TrySetResult(WriteResult.Skipped);

continue;
}
continue;
}


// Calculate the next sequence number from the calculated previous messages.
lastSeqNo = Math.Max(lastSeqNo, sendData.MessageData.SeqNo);
// Calculate the next sequence number from the calculated previous messages.
lastSeqNo = Math.Max(lastSeqNo, sendData.MessageData.SeqNo);

copyInFlightMessages.Enqueue(sendData);
}
copyInFlightMessages.Enqueue(sendData);
}

var newSession = new WriterSession(
config: _config,
stream: stream,
lastSeqNo: lastSeqNo,
sessionId: initResponse.SessionId,
initialize: Initialize,
logger: _logger,
inFlightMessages: _inFlightMessages
);

if (!copyInFlightMessages.IsEmpty)
{
await newSession.Write(copyInFlightMessages); // retry prev in flight messages
}

var newSession = new WriterSession(
config: _config,
stream: stream,
lastSeqNo: lastSeqNo,
sessionId: initResponse.SessionId,
initialize: Initialize,
logger: _logger,
inFlightMessages: _inFlightMessages
);

if (!copyInFlightMessages.IsEmpty)
_session = newSession;
newSession.RunProcessingWriteAck();
WakeUpWorker(); // attempt send buffer
}
finally
{
await newSession.Write(copyInFlightMessages); // retry prev in flight messages
_clearInFlightMessagesSemaphoreSlim.Release();
}

_session = newSession;
newSession.RunProcessingWriteAck();
WakeUpWorker(); // attempt send buffer
}
catch (Driver.TransportException e)
{
_logger.LogError(e, "Transport error on creating WriterSession");

_ = Task.Run(Initialize, _disposeCts.Token);
}
catch (OperationCanceledException)
{
_logger.LogWarning("Initialize writer is canceled because it has been disposed");
}
}

public void Dispose()
Expand All @@ -318,6 +342,8 @@ internal record MessageSending(MessageData MessageData, TaskCompletionSource<Wri
internal interface IWriteSession
{
Task Write(ConcurrentQueue<MessageSending> toSendBuffer);

bool IsActive { get; }
}

internal class NotStartedWriterSession : IWriteSession
Expand All @@ -343,6 +369,8 @@ public Task Write(ConcurrentQueue<MessageSending> toSendBuffer)

return Task.CompletedTask;
}

public bool IsActive => true;
}

internal class DummyWriterSession : IWriteSession
Expand All @@ -357,6 +385,8 @@ public Task Write(ConcurrentQueue<MessageSending> toSendBuffer)
{
return Task.CompletedTask;
}

public bool IsActive => false;
}

internal class WriterSession : TopicSession<MessageFromClient, MessageFromServer>, IWriteSession
Expand Down
1 change: 1 addition & 0 deletions src/Ydb.Sdk/tests/Ado/YdbCommandTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -156,6 +156,7 @@ public async Task CloseAsync_WhenDoubleInvoke_Idempotent()
var ydbDataReader = await ydbCommand.ExecuteReaderAsync();

Assert.True(await ydbDataReader.NextResultAsync());
Assert.False(await ydbDataReader.NextResultAsync());
await ydbDataReader.CloseAsync();
await ydbDataReader.CloseAsync();
Assert.False(await ydbDataReader.NextResultAsync());
Expand Down
9 changes: 6 additions & 3 deletions src/Ydb.Sdk/tests/Ado/YdbSchemaTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -86,8 +86,9 @@ public async Task GetSchema_WhenTablesWithStatsCollection_ReturnAllTables()
{
tableNames.Remove(row["table_name"].ToString()!);

Assert.NotNull(row["rows_estimate"]);
Assert.NotNull(row["creation_time"]);
Assert.Equal(DBNull.Value, row["modification_time"]);
Assert.NotNull(row["modification_time"]);
}

Assert.Empty(tableNames);
Expand All @@ -96,15 +97,17 @@ public async Task GetSchema_WhenTablesWithStatsCollection_ReturnAllTables()
Assert.Equal(1, singleTable1.Rows.Count);
Assert.Equal(table1, singleTable1.Rows[0]["table_name"].ToString());
Assert.Equal("TABLE", singleTable1.Rows[0]["table_type"].ToString());
Assert.NotNull(singleTable1.Rows[0]["rows_estimate"]);
Assert.NotNull(singleTable1.Rows[0]["creation_time"]);
Assert.Equal(DBNull.Value, singleTable1.Rows[0]["modification_time"]);
Assert.NotNull(singleTable1.Rows[0]["modification_time"]);

var singleTable2 = await ydbConnection.GetSchemaAsync("TablesWithStats", new[] { table2, null });
Assert.Equal(1, singleTable2.Rows.Count);
Assert.Equal(table2, singleTable2.Rows[0]["table_name"].ToString());
Assert.Equal("TABLE", singleTable2.Rows[0]["table_type"].ToString());
Assert.NotNull(singleTable2.Rows[0]["rows_estimate"]);
Assert.NotNull(singleTable2.Rows[0]["creation_time"]);
Assert.Equal(DBNull.Value, singleTable2.Rows[0]["modification_time"]);
Assert.NotNull(singleTable2.Rows[0]["modification_time"]);

// not found case
var notFound = await ydbConnection.GetSchemaAsync("Tables", new[] { "not_found", null });
Expand Down
8 changes: 4 additions & 4 deletions src/Ydb.Sdk/tests/Topic/WriterUnitTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -334,7 +334,7 @@ public async Task Initialize_WhenNotSupportedCodec_ThrowWriterExceptionOnWriteAs
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.Write({ "writeRequest": { "messages": [ { "seqNo": "1", "createdAt": "2024-12-03T12:44:23.276086Z", "data": "ZAAAAAAAAAA=", "uncompressedSize": "8" } ], "codec": 1 } })
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.MoveNextAsync()
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.Current
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.MoveNextAsync()
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.MoveNextAsync() [Maybe]
*/
[Fact]
public async Task WriteAsync_WhenTransportExceptionOnWriteInWriterSession_ShouldReconnectAndReturnWriteResult()
Expand Down Expand Up @@ -391,7 +391,7 @@ public async Task WriteAsync_WhenTransportExceptionOnWriteInWriterSession_Should

Assert.Equal(PersistenceStatus.Written, (await writer.WriteAsync(100L)).Status);
_mockStream.Verify(stream => stream.Write(It.IsAny<FromClient>()), Times.Exactly(4));
_mockStream.Verify(stream => stream.MoveNextAsync(), Times.Exactly(5));
_mockStream.Verify(stream => stream.MoveNextAsync(), Times.AtLeast(4));
_mockStream.Verify(stream => stream.Current, Times.Exactly(3));
}

Expand All @@ -410,7 +410,7 @@ public async Task WriteAsync_WhenTransportExceptionOnWriteInWriterSession_Should
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.MoveNextAsync() <- return true after write message
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.Write({ "writeRequest": { "messages": [ { "seqNo": "1", "createdAt": "2024-12-03T14:06:06.408114Z", "data": "ZAAAAAAAAAA=", "uncompressedSize": "8" } ], "codec": 1 } })
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.Current
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.MoveNextAsync()
IBidirectionalStream<StreamWriteMessage.Types.FromClient, StreamWriteMessage.Types.FromServer>.MoveNextAsync() [Maybe]
*/
[Fact]
public async Task WriteAsync_WhenTransportExceptionOnProcessingWriteAck_ShouldReconnectThenReturnWriteResult()
Expand Down Expand Up @@ -466,7 +466,7 @@ public async Task WriteAsync_WhenTransportExceptionOnProcessingWriteAck_ShouldRe
Assert.Equal(PersistenceStatus.Written, (await writer.WriteAsync(100L)).Status);

_mockStream.Verify(stream => stream.Write(It.IsAny<FromClient>()), Times.Exactly(3));
_mockStream.Verify(stream => stream.MoveNextAsync(), Times.Exactly(5));
_mockStream.Verify(stream => stream.MoveNextAsync(), Times.AtLeast(4));
_mockStream.Verify(stream => stream.Current, Times.Exactly(3));
}

Expand Down
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