Implementing predictable transactions to counteract covert-channel attacks in differential privacy systems presents several challenges. These include ensuring that each transaction is completed within a tightly controlled timeframe to avoid leaks through timing analysis. Moreover, the system must handle transactions that exceed their execution time by aborting them and ensuring that no partial or sensitive data leaks through these aborts. This requires robust mechanisms for managing and isolating transaction states, which can be complex and potentially impact system performance and scalability.