What is eventual consistency?
Eventual consistency is one of the common data consistency models in distributed database systems. Considered one of the “weak” consistency schemes, eventual consistency means that when a specific data item is added or updated, that given time the value of that data item will eventually be consistent across database nodes or replicas, thus the name. For some applications, eventual consistency is sufficient – especially for datasets that are not updated frequently (or at all). And eventual consistency model helps ensure high availability of the data at the risk of some data being stale or out of date. Eventual consistency can be a problem for application developers because it puts them at risk of putting data into an inconsistent state.
For many applications, eventual consistency is not suitable and strong consistency is required. Some distributed database systems – including Aerospike – offer more than one consistency model. Strong consistency requires more processing and cluster resources, making weaker consistency models attractive for workloads that can withstand the consequences of inconsistent data.