Eventually consistent: The updates propagate, when there are no updates over a certain period of time defied for a particular application. Hence, the systems where BASE is the key requirement for reliability, the potential of the data changes essentially slows down.
A lot of databases on websites prefer Speed, Performance and Scalability instead of pure Consistency and integrity of data. Availability of BASE system is ensured through accepting partial partitions. Protocols such as Gossip can be used to replicate data optimistically and later heal any problems that arise . ‘‘Updates are applied in the first-tier, but then passed to inner-tier services which might apply them in different orders’’ .
The elasticity of storage and server resources is at the crux of BASE paradigm. BASE databases use strategies to have Consistency, Atomicity and Partition tolerance ‘‘eventually’’. BASE does not flout CAP theorem, but works around it. If users are partitioned across five database servers, BASE design encourages crafting operations in such a way that a user database failure impacts only the 20% of the users on that particular host.
The following subsections discuss about the BASE properties of
some of the mostly used NoSQL.