How can the ordering of Kafka consumption be ensured?

In Kafka, utilizing the Kafka Consumer API can ensure the order of message consumption. Here are a few methods to guarantee the order of consumption.

1. The consumption order of a single Partition is guaranteed by splitting the messages of a Topic into multiple Partitions, each consumed by only one Consumer, ensuring that messages within that Partition are consumed in order. This is the default consumption order guarantee in Kafka.
2. Specify Message Key: When a producer sends a message, they can assign a Key to each message. Kafka ensures that messages with the same Key are allocated to the same Partition, allowing consumers to group messages by Key to maintain their order.
3. Setting the max.poll.records parameter in Consumer: This parameter determines the maximum number of records returned by each poll call. By setting this value to 1, only one message will be consumed at a time, ensuring the order of consumption.
4. Manually commit offset: By manually committing offset after consuming messages, it ensures that messages are processed and committed correctly, thus ensuring the order of consumption.

It should be noted that the above methods can only guarantee the order of consumption within a single Partition. If there are multiple Partitions, the order of consumption for the entire Topic cannot be guaranteed. To ensure the order of consumption for the entire Topic, the number of Partitions for the Topic can be set to 1, but this will limit Kafka’s throughput. If higher throughput is required, other methods can be used to handle the issue of consumption order, such as performing sorting operations on the consumer side.