void RollbackLocal()
{
Debug.Assert(_connector != null, "No connector");
Debug.Assert(_localTx != null, "No local transaction");
Log.Debug($"Single-phase transaction rollback (localid={_txId})", _connector.Id);
var attempt = 0;
while (true)
{
try
{
_localTx.Rollback();
return;
}
catch (NpgsqlOperationInProgressException)
{
// Repeatedly attempts to rollback, to support timeout-triggered rollbacks that occur
// while the connection is busy.
// This really shouldn't be necessary, but just in case
if (attempt++ == MaximumRollbackAttempts)
{
throw new Exception($"Could not roll back after {MaximumRollbackAttempts} attempts, aborting. Transaction is in an unknown state.");
}
Log.Warn($"Connection in use while trying to rollback, will cancel and retry (localid={_txId}", _connector.Id);
_connector.CancelRequest();
// Cancellations are asynchronous, give it some time
Thread.Sleep(500);
}
}
}
/// <summary>
/// Cancels and terminates an ongoing operation. Any data already written will be discarded.
/// </summary>
public void Cancel()
{
CheckDisposed();
if (CanWrite)
{
_isDisposed = true;
_writeBuf.EndCopyMode();
_writeBuf.Clear();
_connector.SendMessage(new CopyFailMessage());
try
{
var msg = _connector.ReadMessage();
// The CopyFail should immediately trigger an exception from the read above.
_connector.Break();
throw new NpgsqlException("Expected ErrorResponse when cancelling COPY but got: " + msg.Code);
}
catch (PostgresException e)
{
if (e.SqlState == "57014")
{
return;
}
throw;
}
}
else
{
_connector.CancelRequest();
}
}
/// <summary>
/// Cancels an ongoing export.
/// </summary>
public void Cancel()
{
_connector.CancelRequest();
}