DEADLOCK DETECTION IN RTDDBMS USING DYNAMIC 2PL PROTOCOL

Abstract

A Real-time distributed database system (RTDDBS) is vastly used in areas such as computer-integrated manufacturing, the stock market, banking, and command and control systems, reservation systems, automatic teller machines and. advanced scientific research etc. In RTDDBMS transactions should be executed within the timing constrains and must preserve the consistency of the database. In such a system deadlocks may occur when a set of transactions are circularly waiting for each other to release resources. Deadlocks delay the processing time of transaction, reduces resource utilization and transaction throughput. Thus, the transaction may not be completed within the timing constraints specified. This led to the development of the efficient deadlock detection and resolution methods. In this dissertation, a simulation model using Dynamic 2PL protocol is developed and existing deadlock methods are surveyed. Finally new deadlock detection method is proposed and its performance is compared with Obermark's path-pushing algorithm and timeout approaches based on the following parameters: the number of messages, the restart ratio, the throughput and the response time are compared by varying timeout values and number of active transactions. The simulation software is developed using C and is tested on Linux 9.0 platforms, running on a 2.1 GHz, Pentium PC. iii