AN IMPROVED FAILURE RECOVERY ALGORITHM IN TWO-PHASE COMMIT PROTOCOL FOR TRANSACTION ATOMICITY

[摘要] Distributed database systems poses different problems when accessing distributed and replicated databases. Two-Phase Commit protocol (2PC) is a standard algorithm for safeguarding the ACID properties of transactions in distributed systems. It ensures that every single transaction in a distributed system is executed to its completion or one of its operations is committed. In a distributed database system, a transaction blocks during Two-Phase Commit (2PC) processing if the coordinator site fails and at the same time some participant site has declared itself ready to commit the transaction. The blocking phenomena reduce the availability of the system since the participants keep locks on resources until they receive the next message from the coordinator after its recovery. A backup coordinator was employed to deal with the problem but it introduced more communication overheads. This paper addresses the problem of transaction blocking while reducing communication overheads using a simulation algorithm. The simulation algorithm was developed using Jcreator with mySQL acting as a back end data manager, the Bitronix transaction manager (BTM) which is a simple but complete implementation of Java applications. Bitronix transaction manger is a perfect choice for a project using transaction capabilities by sing Java Transfer Manager (JTM) facade. The simulation transaction algorithm will minimize coordinator failure problem in distributed transactions.