BASE

BASE is the weak-consistency NoSQL model: basically available, soft state, eventually consistent — trading strong consistency for availability and scalability.

Purpose

To provide high availability and horizontal scaling for distributed systems while accepting temporary inconsistency.

Mechanism

Basically Available: responses continue despite partial failures. Soft State: state may diverge (and must converge). Eventually Consistent: once updates stop, all replicas converge to the same value. The opposite of ACID; the trade-off is dictated by the CAP theorem.

Use cases

Large-scale distributed storage
CDNs and caches
Social activity feeds
Shopping carts and recommendations

Examples

Input

Brief inconsistency after a write

Output

All replicas eventually converge

Eventual consistency

Common errors

Using BASE when the business needs strong consistency: Use ACID systems for finance and similar domains

Related terms

ACID is the four properties of relational transactions: atomicity (all or nothing), consistency (constraints preserved), isolation (concurrency without interference), and durability (committed data is never lost).

The CAP theorem states that under network partition a distributed system can satisfy only one of consistency (C) or availability (A); all three cannot hold at once.

NoSQL is the umbrella term for non-relational databases, including document, key-value, column-family, and graph models, designed for scalability and flexible schemas.

References