batch-processing

Batch processing Service Bus sessions without duplicating work requires a BackgroundService that uses AcceptNextSessionAsync to manually accept sessions, groups messages via ReceiveMessagesAsync, and deduplicates by SourceId before dispatching a single batch request. This pattern prevents resource exhaustion and ensures predictable failure handling.

Using a BackgroundService instead of ServiceBusSessionProcessor for batch processing provides controlled concurrency via SemaphoreSlim. This manual session acceptance approach replaces inappropriate processor usage by ensuring predictable simultaneous session limits, proper batch retrieval, and coordinated complete or abandon semantics for failure handling.

Handling dead-lettered messages when aggregating Service Bus sessions requires a paired DLQ handler that processes dead-lettered messages individually. This robust error strategy works alongside the main batch dispatch, applying proper complete and abandon semantics based on the specific processing outcome of each message.

Yes, you can use MediatR to dispatch aggregated Service Bus messages by sending a single BatchItemChanged request. After the BackgroundService batches messages and deduplicates them by SourceId, it forwards the aggregated request to IMediator, completing or abandoning the original messages based on the dispatch outcome.

Limiting concurrency when accepting Service Bus sessions manually requires a SemaphoreSlim to restrict simultaneous session processing. By wrapping the AcceptNextSessionAsync and ReceiveMessagesAsync calls with the semaphore, the BackgroundService ensures that the microservice aggregates related messages without overwhelming system resources.