BASE vs ACID
Two contrasting sets of properties that describe how data stores handle consistency and availability. Understanding both is essential for selecting the right storage model in a given architectural context.
ACID
Properties of traditional relational databases designed for correctness above all else.
| Property | Meaning |
|---|---|
| Atomicity | A transaction either fully succeeds or fully fails — no partial state |
| Consistency | Every transaction brings the database from one valid state to another |
| Isolation | Concurrent transactions behave as if executed sequentially |
| Durability | Committed transactions survive crashes |
ACID guarantees strong consistency but typically sacrifices availability and horizontal scalability, especially under network partitions (see CAP Theorem).
BASE
Properties common in distributed and NoSQL databases that prioritize availability and partition tolerance over strict consistency.
| Property | Meaning |
|---|---|
| Basically Available | The system guarantees availability (though responses may be stale) |
| Soft state | State may change over time even without input, as the system converges |
| Eventually consistent | Given no new writes, all nodes will converge to the same value |
BASE systems trade immediate consistency for scalability and fault tolerance. See Eventual Consistency.
Choosing Between Them
| Use ACID when… | Use BASE when… |
|---|---|
| Financial transactions | Social feeds, view counts |
| Inventory that must not oversell | Product catalogs, user preferences |
| Regulatory or audit requirements | High-throughput write workloads |
| Strong consistency is non-negotiable | Temporary inconsistency is tolerable |
Many modern systems use a hybrid approach: ACID for core transactional data, BASE for read-optimized or high-volume secondary stores.
Related Concepts
- CAP Theorem — the fundamental theorem that explains why BASE properties emerge in distributed systems
- PACELC Theorem — extends CAP to cover the latency vs. consistency trade-off during normal operation
- Eventual Consistency — the consistency model at the heart of BASE
- Consistency Models — the broader spectrum of consistency guarantees
- CQRS — often used alongside BASE stores on the read side