Role of Transaction Processing System
3 Pages Posted: 30 Dec 2009
Date Written: December 29, 2009
A Transaction Processing System or Transaction Processing Monitor is a set of information which process the data transaction in database system that monitors transaction programs.The essence of a transaction program is that it manages data that must be left in a consistent state. If an electronic payment is made, the amount must be either both withdrawn from one account and added to the other, or none at all. In case of a failure preventing transaction completion, the partially executed transaction must be rolled back by the TPS. While this type of integrity must be provided also for batch transaction processing, it is particularly important for online processing as of an airline seat reservation system is accessed by multiple operators, after an empty seat inquiry, the seat reservation data must be locked until the reservation is made, otherwise another user may get the impression a seat is still free while it is actually being booked at the time. Without proper transaction monitoring, double bookings may occur. Other transaction monitor functions include deadlock detection and resolution (deadlocks may be inevitable in certain cases of cross-dependence on data), and transaction logging (in journals) for forward recovery in case of massive failures.
Transaction Processing is not limited to application programs. The journaled file system provided with IBMs AIX Unix operating system employs similar techniques to maintain file system integrity, including a journal.
Keywords: transaction, deadlock
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