In theoretical computer science, the CAP theorem, also known as Brewer’s theorem, states that it is impossible for a distributed computer system to simultaneously provide all three of the following guarantees: Consistency, Availability and Partition tolerance.
- Consistency means that all nodes see the same data at the same time.
- Availability means that there is a guarantee that every request receives a response about whether it succeeded or failed.
- Partition tolerance means that the system continues to operate despite arbitrary partitioning due to network failures.
While traditional databases mainly focuses on consistency and availability, big data technologies focuses on Availability and Partition tolerance, in general.