When is data sent in round robin?

When is data sent in round robin?

• A. When the key is non-null
• B. When the key is set to null
• C. When the key is hashed
• D. When there are multiple partitions

Answer: (B)

Data is sent in round robin when there is no key to determine the target partition. The partitioner normally hashes the message key to choose a specific partition, ensuring that records with the same key tend to end up in the same partition. When the key is null, there’s nothing to hash, so the partitioner distributes messages across the available partitions in turn to balance the load. This approach makes sense only if there are multiple partitions; with a single partition, all data still goes to that one.

Data is sent in round robin when there is no key to determine the target partition. The partitioner normally hashes the message key to choose a specific partition, ensuring that records with the same key tend to end up in the same partition. When the key is null, there’s nothing to hash, so the partitioner distributes messages across the available partitions in turn to balance the load. This approach makes sense only if there are multiple partitions; with a single partition, all data still goes to that one.