Can you explain the concept of the minimal offset that a consumer can handle in Kafka?

In Apache Kafka, the minimum offset is the position in a topic partition from which a consumer can start reading messages.

Each message in a partition has a unique offset — an integer index indicating its position.

The consumer stores the current offset to know where to continue reading after a restart or pause.

The minimum offset that the consumer can process depends on:

• The offset from which it started reading (for example, earliest — from the very first available message, latest — from new messages).
• The offset stored in Kafka (for example, if old messages were deleted due to retention policies, the minimum available offset will move forward).

Thus, the minimum offset is the smallest offset available for reading in a partition, and the consumer cannot read messages with a smaller offset if they have been deleted or are unavailable.