Fix RocketMQ Duplicate Message Consumption

The issue of duplicate consumption in RocketMQ typically occurs when the consumer encounters an exception, network timeout, or other issues while processing a message, causing the message to not be consumed correctly and be redelivered to the queue, resulting in duplicate consumption.

There are several main methods to solve the problem of duplicate consumption in RocketMQ.

1. Setting the message consumption mode to cluster mode. In cluster mode, multiple consumers within the same consumer group will evenly distribute messages for consumption. If one consumer encounters an exception, other consumers can continue to consume messages to prevent message duplication.
2. Utilize the message consumption acknowledgment mechanism. After consuming a message, the consumer needs to send an acknowledgment message to the broker, informing the broker that the message has been consumed. The broker will then mark the message as consumed to avoid duplicate consumption.
3. Use the unique identifier of the message for idempotent processing. In the logic of consuming messages, the unique identifier of the message can be used for idempotent processing, which means avoiding duplicate message consumption by checking if the message has already been consumed.
4. Utilize delayed consumption. By setting a delay time when consuming messages, you can wait for a specified period of time before proceeding with consumption, preventing issues such as duplicate consumption due to network timeouts or other abnormalities.

In conclusion, setting consumption patterns, using message acknowledgment mechanism, implementing idempotent processing, and using delayed consumption can effectively address the issue of duplicate consumption in RocketMQ.