TP Moniter~~

What is a transaction processing (TP) monitor?

Transaction processing monitors are defined as acting like an operating system for transaction processing. In other words, it is a program that monitors a transaction as it passes from one stage in a process to another. Nancy (1997) states that transaction processing monitors are part of a software category commonly referred to as middleware.

Krakowiak (2003) defines middleware as ‘the software layer that lies between the operating system and the applications on each side’ of a distributed computing system.

Transaction processing monitors can manage the transfer of data between multiple local and or remote terminals and the application programs that serve them. Transaction processing monitors guarantee that all databases are updated as a single unit. A transaction processing monitor may be used in the tour agency example to ensure all bookings can be successfully made with the airline, hotel and car companies before committing to finalising the process and updating all the databases at the same time.

What purpose does a transaction processing (TP) monitor serve?

As explained by Pachowicz, the purpose of a transaction processing monitor is to ‘manage transactions from their point of origin, on the client, across one or more servers and then back to the original client’. He also goes on to suggest that transaction processing monitors should ensure the ACID properties of transactions (explained earlier) are upheld. Therefore transaction processing monitors perform two major services:

(1) It performs a transaction service that has the ability to execute transactions concurrently while at the same time ensuring integrity.

(2) And it performs an application service to manage multiple resources, for example client, servers and transactional services, all within separate processes. According to Carnegie Mellon Software Engineering Institute, Transaction processing monitors provide:

- The ability to update multiple database management systems in a single transaction.

- Connectivity to a variety of data sources including flat files, non-relational database management system, and the mainframe.

- The ability to attach priorities to transactions.

- Robust security.