What are BASE properties in distributed databases?

BASE (Basically Available, Soft State, Eventually Consistent) is a set of properties that guide the design of distributed databases, prioritizing availability and flexibility over strict consistency. Unlike ACID (Atomicity, Consistency, Isolation, Durability), which enforces immediate consistency and transactional guarantees, BASE acknowledges the challenges of distributed systems—like network partitions and latency—and opts for a more pragmatic approach. This makes BASE-based systems well-suited for large-scale, highly available applications where some temporary inconsistency is acceptable.

Basically Available ensures the system remains operational even during partial failures. For example, if a distributed database like Apache Cassandra experiences a node outage, read and write requests are redirected to other nodes, allowing the system to continue functioning. This prioritizes uptime over perfect data accuracy in the moment. Soft State means the system’s state can evolve over time without immediate updates. Data might exist in an intermediate, non-guaranteed state (e.g., cached values or uncommitted writes) until the system reconciles it. Eventual Consistency guarantees that, given enough time without new updates, all nodes will converge to the same data state. For instance, in a social media app, a user’s post might not appear instantly for all followers globally, but it will propagate to all servers eventually.

BASE is critical in scenarios where high availability and scalability outweigh the need for strict consistency. For example, e-commerce platforms often use BASE-compliant databases for inventory management. If two users attempt to purchase the last item in stock, the system might temporarily show the item as available to both, resolving the conflict later by canceling one order. Developers must design applications to handle these temporary inconsistencies—such as displaying a “processing” message or retrying failed operations. While BASE introduces complexity in handling stale data, it enables systems to scale horizontally and maintain performance under heavy loads, making it a cornerstone of modern distributed architectures.