Concurrency Control Mechanism for Nested Transactions in Mobile Environment

Abstract

In mobile environment, mobile host can initiate transactions and that transactions may be executed at mobile host or fixed host. Most of the transactions use in mobile environment is flat transactions. In modern world, most of the applications are complex and long-running. Flat transactions could not work properly in complex and long-running applications. Moreover, flat transactions can be performed only commit or rollback and cannot save intermediate results. If transactions rollback, the whole transaction is re-started. To solve this problem, we proposed a method that based on closed nested transactions because nested transactions are suited for complex application and can save intermediate result.  Proposed system is based on existing Two-Shadow Speculative Concurrency Control (SCC-2S) mechanism that solves concurrency control problem (read-write conflict) for nested transactions and complex application. Proposed system solves the facts that could not solve (write-write conflict) in existing SCC-2S algorithm and also adds Priority Control mechanism to improve the performance of the system and to reduce miss deadlines. This method is intended for Mobile Real-Time Database System (MRTDBS). Concurrency Control will perform at the Fixed Host and the results are returned back to the corresponding Mobile Hosts.