Concurrency Issues of Distributed Advance Transaction Process

The transactional model for distributed system has been around for many years and it is considered a well-established and mature technology. The traditional transaction model, although suitable for conventional database applications such as banking and airline reservation systems, does not provide much flexibility and high performance when used for complex applications such as object oriented systems, long-lived transactions, or distributed systems. Nested transactions have been proposed to overcome the limitations of flat transaction model. Nested transactions extend the notion that transactions are flat entities by allowing a transaction to invoke atomic transactions as well as atomic operations. They provide safe concurrency within transaction, allow potential internal parallelism to be exploited and offer an appropriate control structure to support their execution. In this paper we describe distributed database system and their transaction process. In this paper we also describe advance-nested transactions where the transactions from one system interact with the transactions from another system. Such nested transactions can expect to become more important with the introduction of network operating systems and heterogeneous distributed database systems. Finally, we will study about concurrency issue of nested transaction with respect to distributed database. Keyword: Distributed database, database, distributed processing, transaction, transaction manager, nested transaction, flat transaction, atomicity, consistency, isolation, durability, subtransaction.