Weak Consistency
Weak consistency does not guarantee that reads immediately see writes, only that they may eventually — a generalization of eventual consistency.
Purpose
To understand what weak guarantees mean in the consistency hierarchy and design systems with modest consistency requirements.
Mechanism
Reading immediately after a write may return a stale value, and the system gives no guarantee of when consistency is reached. It subsumes eventual consistency, causal consistency, and other subtypes. Suited to social feeds, counters, and other staleness-tolerant scenarios.
Use cases
- Social system design
- Counter services
- Low-latency read optimization