REAL-TIME TRANSACTION EXECUTION BASED ON TRANSACTION PRE-ANALYSIS

In a real time database system, transactions can have timing constraints (typically the deadlines), and the transactions which exceed their deadlines can cause catastrophic effects on the system. This requires that the system preanalyze and preplan the execution of transactions. Because of all kinds of uncertain factors (including data I/O, page fault, the dependency among transactions), the transactions have the dynamic unpredictability in the traditional transaction processing. In this paper, a three phased pre analysis strategy is presented for real time transaction processing. In the static pre analysis phase, the system obtains the static information of transactions; In the initial dynamic pre analysis phase, the system constructs an image transaction for a user transaction, and the image transaction is assigned a higher priority than the user transaction. This can ensure that before the user transaction operation, the needed data are in the main memory. During the dynamic pre analysis phase, the transaction dependency graph is constructed and the behavioral correctness, structural correctness, and the time correctness of transactions are achieved in a unique way. This increases the system performance and results in more transactions meeting their deadlines. Extensive experiments are conducted to evaluate the performance of the strategies. The experimental result shows that the proposed strategies have better system performance than that of the traditional ones in terms of less transaction missing their deadlines.