What is ACID and BASE in database theory?
by Daniel J. Power
Data-driven and document-driven decision support systems derive functionality from data stores and databases. Beginning in the late 1990s, distributed computing facilitated deployment of new database architectures and led to post-relational databases. Storing and processing data across multiple computing nodes however creates potential problems in transaction processing. The expansion of the Internet and the need for managing larger data stores faster also led to innovation. In 2000, Eric Brewer popularized the acronym "BASE" in his keynote address at the ACM Symposium titled “Towards Robust Distributed Systems”. Brewer also explained the CAP Theorum. CAP refers to Consistency, Availability and Partition Tolerance. The theorum asserts a distributed, networked system can have only two of these three properties. How are these concepts relevant to decision support?
The traditional standard for reliable transaction processing is summarized by the acronym ACID (Atomicity, Consistency, Isolation, Durability). Decision support requires a less strict standard when static historical data is used. Real-time decision support can adhere to the eventual consistency provided by BASE. The CAP theorum explains the theoretical divide between ACID and BASE compliant databases. Understanding database theory can help decision support designers make good design choices.
Roe (2012; 2013) reviews CAP Theorum, ACID and Base. The CAP theorem states that there are three desirable system requirements for the successful design, implementation and deployment of applications in distributed computing systems. Attaining all three is not however possible. The three are:
Let's examine the ACID requirement for a database transaction system in more detail.
The standards of BASE challenge some of the long held expectations for transaction processing. That's ok because decision support is not transaction processing. Let's review those standards:
Real-time decision support systems can perform satisfactorily is a BASE compliant database environment. Data warehouses have been built with denormalized, historical data for many years. In conclusion, data and document-driven DSS designers need to understand ACID and BASE and the CAP theorum, but historical data that is properly stored is ACID compliant by default. Streaming, real-time data used for decision support can meet BASE standards and that is a reasonable expectation. Decision support needs AP in CAP much more than consistency.
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Last update: 2013-10-12 06:00
Author: Daniel Power
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