Which factor is essential for ensuring efficient transaction processing in queues?

Back-off strategies are essential for ensuring efficient transaction processing in queues because they help manage the frequency of retry attempts after a transaction fails. When a transaction encounters an error, instead of immediately retrying it, back-off strategies introduce a waiting period before the next attempt. This prevents overwhelming the processing system with constant retries, which can lead to increased load and potential failures.

By gradually increasing the time interval between retries, these strategies allow the system to recover or for the underlying issue to resolve itself, thus improving the overall throughput and stability of transaction processing. This approach can minimize resource contention and enhance the reliability of the queue system in handling transactions effectively.

Other options do not directly contribute to the efficiency of transaction processing in the same way. Randomization of retry attempts, for example, may help in some scenarios but does not systematically address the load and recovery mechanisms essential for queue management. Minimizing user roles and maximizing UI dimensions do not play a significant role in the transaction processing logic within queues, as they relate more to user access and interface design than to the backend processing efficiency.