A Kafka consumer can consume the messages from a specific offset in a given topic partition or reset the offset to the partition’s beginning or end.
In this tutorial, we will learn what seek to the beginning and seek to the end mean for a Kafka consumer.
What Is Kafka Consumer Seek to Beginning
The “Seek to Beginning” is a feature of the Kafka Seek API which allows a Kafka consumer application to read the messages from the first offset in a given partition. Using the “Seek to Beginning” feature, the consumer starts from the first offset in the partition and reads all the subsequent messages.
An offset is a log of messages which is produced to a given Kafka topic and is stored in a specific partition. Each time a new message is written to a partition, the offset value is incremented by one. Hence, when the consumer seeks the beginning, it resets to the first offset in that partition.
We can use the seekToBeginning() method to reset the consumer’s position to the first offset in the partition. The method takes no arguments; we can call it at any point in the consumer’s lifetime.
NOTE: Calling the seekToBeginning() method forces the consumer to discard the previously read messages and start from scratch.
What Is Kafka Consumer Seek to End
As you can guess, the “Seek to End” is the opposite of seek to beginning feature. This feature allows the consumer client to read the messages from the last offset in a given partition.
This forces the consumer to skip to the last offset regardless of the current position. We can use the seekToEnd() method to allow the consumer to skip to the last offset of the partition.
NOTE: Calling the seekToEnd() method forces the consumer to skip every other message in the partition and only read the new messages that are produced after the method call.
You can learn more about seekToBeginning and seekToEnd() methods in the documentation as provided in the following link:
Conclusion
We understood what the seek to beginning and seek to end features are, what they do, and how they work in a Kafka consumer. Feel free to explore the feature usage in your Kafka consumer.
