Databases & Data Storage
Strong Consistency
Definition
Strong consistency is a consistency model where all accesses to a data item are guaranteed to see the most recent completed write. Once a write is complete, any subsequent read will see that value.
Why It Matters
It is the most intuitive consistency model and is what developers typically expect. It simplifies application logic because you don't have to worry about reading stale data. It is a core tenet of the ACID model.
Contextual Example
In a banking system, when you make a deposit, any subsequent check of your balance must reflect that deposit immediately. This requires strong consistency.
Common Misunderstandings
- Achieving strong consistency in a distributed system can be costly in terms of performance and availability, as it requires coordination between all data replicas.
- Traditional single-node relational databases are strongly consistent by nature.