Eventual consistency means eventually, when all SERVICE logic is executed, the system is left in a consistent state. This concept is widely used in distributed systems to achieve high availability. It informally guarantees that, if no new updates are made to a given data item, eventually all ACCESSES to that item will RETURN the last updated value.

In NoSQL systems, the eventual consistent services are often classified as providing BASE (Basically Available, Soft state, Eventual consistency) and in RDMS, it is classified as ACID (Availability, Consistency, Isolation and Durability). Leading NoSQL databases like Riak, Couchbase, and DynamoDB provide CLIENT applications with a guarantee of “eventual consistency”. Others, like MongoDB and Cassandra are eventually consistent in some configurations.

Eventual consistency means eventually, when all service logic is executed, the system is left in a consistent state. This concept is widely used in distributed systems to achieve high availability. It informally guarantees that, if no new updates are made to a given data item, eventually all accesses to that item will return the last updated value.

In NoSQL systems, the eventual consistent services are often classified as providing BASE (Basically Available, Soft state, Eventual consistency) and in RDMS, it is classified as ACID (Availability, Consistency, Isolation and Durability). Leading NoSQL databases like Riak, Couchbase, and DynamoDB provide client applications with a guarantee of “eventual consistency”. Others, like MongoDB and Cassandra are eventually consistent in some configurations.