It is difficult for a distributed real-time transaction to satisfy its deadline because of the complexities of its commitment processing. A new commit protocol called A2SC (active double space commit) is proposed, which cater for the distributed real-time transaction commitment processing. All kinds of dependencies caused from data conflicts access are analyzed. When data conflicts between the prepared transaction and the execution transactions occur, A2SC allows the execution transactions to access the locked data optimistically in a controlled manner. When the prepared transaction aborts, only transactions in its abort dependency set are aborted. Furthermore, a notion of fruitless run is proposed. When a transaction finds fruitless run, it will actively abort. Extensive simulation experiments have been performed to compare the performance of the A2SC with other protocols such as the base protocol, the PROMPT and the DDCR. The simulation results show that A2SC is highly successful in minimizing the number of missed transactions deadlines. So A2SC caters for high-performance distributed real-time transaction.