Strict Serializability is Harmless: A New Architecture for Enterprise Applications
Despite many evolutions in the software architecture of enterprise applications, one thing has remained the same over the years: They still use a relational database both for data persistence and transactional support. We argue that such design, once justified by hardware limitations, endured mostly for legacy reasons and is no longer adequate for a significant portion of modern applications running in a new generation of multicore machines with very large memories.
We propose a new architecture for enterprise applications that uses a Software Transactional Memory for transactional support at the application server tier, thereby shifting the responsibility of transaction control from the database to the application server. The database tier remains in our architecture with the sole purpose of ensuring the durability of data.
With this change we are able to provide strictly serializable transaction semantics, and we do so with increased performance. Thus, we claim that strict serializability is harmless, in the sense that programmers no longer have to trade correctness for performance for a significant class of applications. We have been using this new architecture since 2005 in the development of real-world complex object-oriented applications, and we present statistical data collected over several years about the workload patterns of these applications, revealing a surprisingly low rate of write transactions.