private async Task ConfirmationTask(TransactionRecord <TState> record)
{
try
{
var tasks = new List <Task>();
record.LastConfirmationAttempt = DateTime.UtcNow;
foreach (var p in record.WriteParticipants)
{
if (p != thisParticipant)
{
tasks.Add(p.Confirm(record.TransactionId, record.Timestamp));
}
}
await Task.WhenAll(tasks);
confirmationTasks.Remove(record.TransactionId);
// all prepare records have been removed from all participants.
// Now we can remove the commit record.
storageBatch.Collect(record.TransactionId);
storageWorker.Notify();
}
catch (Exception e)
{
// we are giving up for now.
// if pinged or reloaded from storage, we'll try again.
logger.Warn(333, $"Could not notify/collect:", e);
}
}
public void Add(TransactionRecord <T> entry)
{
// ensure we have room
if (buffer == null)
{
buffer = new TransactionRecord <T> [DefaultCapacity];
}
else if (Count == buffer.Length)
{
var newbuffer = new TransactionRecord <T> [buffer.Length * 2];
Array.Copy(buffer, pos, newbuffer, 0, buffer.Length - pos);
Array.Copy(buffer, 0, newbuffer, buffer.Length - pos, pos);
buffer = newbuffer;
pos = 0;
}
if (Count > 0 && buffer[(pos + Count - 1) % buffer.Length].Timestamp > entry.Timestamp)
{
throw new ArgumentException($"elements must be added in timestamp order, but {entry.Timestamp:o} is before {buffer[(pos + Count - 1) % buffer.Length].Timestamp:o}", nameof(entry));
}
// add the element
buffer[(pos + Count) % buffer.Length] = entry;
Count++;
}
private void EnqueueCommit(TransactionRecord <TState> record)
{
try
{
if (logger.IsEnabled(LogLevel.Trace))
{
logger.Trace($"start two-phase-commit {record.TransactionId} {record.Timestamp:o}");
}
commitQueue.Add(record);
// additional actions for each commit type
switch (record.Role)
{
case CommitRole.ReadOnly:
{
// no extra actions needed
break;
}
case CommitRole.LocalCommit:
{
// process prepared messages received ahead of time
if (unprocessedPreparedMessages != null &&
unprocessedPreparedMessages.TryGetValue(record.Timestamp, out var info))
{
if (info.Status == TransactionalStatus.Ok)
{
record.WaitCount -= info.Count;
}
else
{
AbortCommits(info.Status, commitQueue.Count - 1);
lockWorker.Notify();
}
unprocessedPreparedMessages.Remove(record.Timestamp);
}
break;
}
case CommitRole.RemoteCommit:
{
// optimization: can immediately proceed if dependency is implied
bool behindRemoteEntryBySameTM =
commitQueue.Count >= 2 &&
commitQueue[commitQueue.Count - 2] is TransactionRecord <TState> rce &&
rce.Role == CommitRole.RemoteCommit &&
rce.TransactionManager.Equals(record.TransactionManager);
if (record.NumberWrites > 0)
{
storageBatch.Prepare(record.SequenceNumber, record.TransactionId, record.Timestamp, record.TransactionManager, record.State);
}
else
{
storageBatch.Read(record.Timestamp);
}
storageBatch.FollowUpAction(() =>
{
if (logger.IsEnabled(LogLevel.Trace))
{
logger.Trace($"prepared {record.TransactionId} {record.Timestamp:o}");
}
record.PrepareIsPersisted = true;
if (behindRemoteEntryBySameTM)
{
// can send prepared message immediately after persisting prepare record
record.TransactionManager.Prepared(record.TransactionId, record.Timestamp, thisParticipant, TransactionalStatus.Ok).Ignore();
record.LastSent = DateTime.UtcNow;
}
});
break;
}
default:
{
logger.LogError(777, "internal error: impossible case {CommitRole}", record.Role);
throw new NotSupportedException($"{record.Role} is not a supported CommitRole.");
}
}
}
catch (Exception e)
{
logger.Error(666, $"transaction abort due to internal error in {nameof(EnqueueCommit)}: ", e);
NotifyOfAbort(record, TransactionalStatus.UnknownException);
}
}
private void NotifyOfAbort(TransactionRecord <TState> entry, TransactionalStatus status)
{
switch (entry.Role)
{
case CommitRole.NotYetDetermined:
{
// cannot notify anyone. TA will detect broken lock during prepare.
break;
}
case CommitRole.RemoteCommit:
{
if (logger.IsEnabled(LogLevel.Trace))
{
logger.Trace($"aborting RemoteCommitEntry {entry.Timestamp:o} status={status}");
}
if (entry.LastSent.HasValue)
{
return; // cannot abort anymore if we already sent prepare-ok message
}
entry.TransactionManager.Prepared(entry.TransactionId, entry.Timestamp, thisParticipant, status).Ignore();
break;
}
case CommitRole.LocalCommit:
{
if (logger.IsEnabled(LogLevel.Trace))
{
logger.Trace($"aborting LocalCommitEntry {entry.Timestamp:o} status={status}");
}
// reply to transaction agent
entry.PromiseForTA.TrySetResult(status);
// tell remote participants
foreach (var p in entry.WriteParticipants)
{
if (p != thisParticipant)
{
p.Cancel(entry.TransactionId, entry.Timestamp, status).Ignore();
}
}
break;
}
case CommitRole.ReadOnly:
{
if (logger.IsEnabled(LogLevel.Trace))
{
logger.Trace($"aborting ReadEntry {entry.Timestamp:o} status={status}");
}
// reply to transaction agent
entry.PromiseForTA.TrySetResult(status);
break;
}
default:
{
logger.LogError(777, "internal error: impossible case {CommitRole}", entry.Role);
throw new NotSupportedException($"{entry.Role} is not a supported CommitRole.");
}
}
}
