The IBM MQ transport supports the following transport transaction modes. Choose a mode based on your requirements for delivery guarantees, performance, and exactly-once processing:
- Transport transaction - Sends atomic with receive
- Transport transaction - Receive only (default)
- Unreliable (transactions disabled)
TransactionScope mode is not supported because the IBM MQ .NET client does not participate in distributed transactions.
Exactly-once message processing without distributed transactions can be achieved with any transport using the Outbox feature.
Sends atomic with receive
In SendsAtomicWithReceive mode, the message receive and all outgoing send/publish operations are committed or rolled back as a single unit of work.
var transport = new IBMMQTransport
{
// ... connection settings ...
TransportTransactionMode = TransportTransactionMode.SendsAtomicWithReceive
};
Messages sent outside of a handler (e.g., via IMessageSession) are not included in the atomic operation.
Receive only
In ReceiveOnly mode, the message receive is transactional. Successfully processed messages are committed. Failed messages are returned to the queue for reprocessing. Outgoing send and publish operations are not part of the receive transaction.
This is the default transaction mode.
var transport = new IBMMQTransport
{
// ... connection settings ...
TransportTransactionMode = TransportTransactionMode.ReceiveOnly
};
If the queue manager connection is lost after processing succeeds but before the transaction commits, the message is redelivered. This can result in duplicate processing. Use the Outbox feature to guarantee exactly-once processing.
Unreliable (transactions disabled)
In None mode (transactions disabled), messages are consumed without any transactional guarantees. If processing fails, the message is lost.
var transport = new IBMMQTransport
{
// ... connection settings ...
TransportTransactionMode = TransportTransactionMode.None
};
This mode should only be used when message loss is acceptable, such as for non-critical telemetry or logging messages. Avoid this mode for business-critical events.