Acknowledgment Batching

The AMPS Java client automatically batches acknowledgments when either of the convenience methods is used. Batching acknowledgments reduces the number of round-trips to AMPS, reducing network traffic and improving overall performance. AMPS sends the batch of acknowledgments when the number of acknowledgments exceeds a specified size, or when the amount of time since the last batch was sent exceeds a specified timeout.

You can set the number of messages to batch and the maximum amount of time between batches, as shown below:

client.setAckBatchSize(10); // Send batch after 10 messages
client.setAckTimeout(1000); // ... or 1 second

The AMPS Java client is aware of the subscription backlog for a subscription. When AMPS returns the acknowledgment for a subscription that contains queues, AMPS includes information on the subscription backlog for the subscription. If the batch size is larger than the subscription backlog, the AMPS Java client adjusts the requested batch size to match the subscription backlog.

60East recommends tuning the batch size to improve application performance. A value of 1/3 of the smallest max_backlog value is a good initial starting point for testing. 60East does not recommend setting the batch size larger than 1/2 of the max_backlog value without testing the setting to ensure that the application does not run out of messages to process while the acknowledgment is being sent to AMPS.