The CAP theorem versus databases with relaxed ACID properties
Lars Frank, Rasmus Ulslev Pedersen, Christian Frank, Niklas Larsson · 2014
The CAP theorem combines the three desirable properties C (data consistency), A (data availability), and P (partition-tolerance: tolerance of inconsistencies between data stored in a distributed database where partitions are allowed). The CAP theorem asserts that any distributed system that uses data from different locations can have at most two of the three desirable CAP properties [5]. The NoSQL movement has applied the CAP theorem as an argument against traditional ACID (atomicity, consistency, isolation, and durability) databases, which prioritize consistency and partition-tolerance at the cost of a potentially low availability. Recently, Brewer [4] has modified the CAP theorem, pointing out that all the CAP properties are more or less continuous, and possible to optimize, weighing them against each other., in practice it is possible for an application area to have both relative high availability and sufficient data consistency, despite the presence of network partitions.