When thinking about Transactions, I think it is fair to say that Transactions are one of the most powerful and frequently used paradigms in Enterprise Computing today. With Transactions, we have a collection of patterns that deal with how concurrency management and recovery control can be handled in possible shared/concurrent environments/contexts and it is this that ensures data/state correctness. It is the key concepts and abstractions of Transactions maintaining data/state consistency in possible concurrent state/data access environments (where failures may occur) that have allowed us as developers and architects to be largely released from having to deal with the tricky aspect of maintaining the correctness of state in concurrent environments in an enterprise application.
Two of the very interesting aspects of Transactions is how trusted they have become and how we perceive them. Concurrency Management and recovery control are some of the more tricky aspects of Enterprise Computing, but yet when leveraging the Transactional paradigm and executing units of work in a concurrent environment in the context of a transaction, we are not overly concerned about isolation or failure as much of the work is done for us by the Transaction Paradigm. This is a testament to the level of trust and adoption that Transactions have achieved as an abstraction and how it has evolved into a framework of runtime services that takes most of the responsibility for concurrency management and recovery control from us as developers and architects. The paradigm of Transactions can be seen as a set of patterns, Interfaces and Contracts that can be leveraged to simplify the transformation from one known state to another and without these Interfaces and Contracts; a lot of code, time and effort has to be spend in making sure that data/state transformations happen in a consistent and all or nothing fashion.
It is these key abstractions in the form of runtime services or frameworks that have provided great productive gains for us as developers and architects, as it allows us to focus on business logic and allows for the underlying runtime services to deal with concurrency management and recovery control. Therefore as we implement application logic, by applying units of work to state, we want the transformation from one state to another to be applied in a consistent (all or nothing) fashion, as well as wanting to be isolated from other parallel activities. As I mentioned in my How should we think of Transactions ? blog posting, I like to think of the Transaction paradigm as a collection of patterns, interfaces and contracts that can be leveraged to tackle the issue of data/state correctness as we group actions into unit of works to transform from one known state to another. Some of this collection of patterns, interfaces and contracts are short running transactions that in the main adhere to the ACID properties but there is a rich portfolio of transactional types that we do not focus on that much and/or maybe perceive as not meeting the ACID properties (see How should we think of Transactions ? and Volatile Transactions & In-Memory Transactions - do they have ACID, ACId or ACI properties?)
Today, the most common example of how the Transaction paradigm can provide concurrency management and recovery control is Database Management Systems (DBMS). Databases (aka DBMS) are themselves another key and often used architectural piece of Enterprise computing. Database Management Systems (DBMS) provide a paramount role in how an Enterprise may store, retrieve and share state/data. But we sometimes draw an association between Databases and Transactions that is so close that they are often perceived as being interchangeable, i.e. Transactions are DB Transactions and nothing else. The close associations between databases systems and transactional processing have been fundamental in bringing the concept of Transactional Processing to the fore, but in my honest opinion I think that the close association may have also brought a narrowing of perception of what are Transactions and Transactional Processing.
I have put together a series of blog postings to share my current views/thoughts! After talking to a few folks about Transactions, it is very interesting to hear the different views and I'm not sure if there is a one size fits all for what is a transaction, but this is the thing about a paradigm and a snappy acronym, it can have a life of its own Maybe we interchange the paradigm, acronym’s and implementations into one fixed view and its this fixed view that maybe causing the issue!