S3 Consistency Model
- Puts (New record) = Read-after-write consistency model
- Updates and Deletes = Eventual consistency model
DynamoDB Consistency Model
- Write = Eventual consistency model
- Read = Eventual consistency model
- Read = Optional – Strong consistency model
Definitions
- Read-after-write consistency model = New objects should be available with out delays to clients.
- Eventual consistency model = “Eventually” all access attempts to a particular item will return the last updated value. There is potential here for stale or old data reads while data replication occurs.
- Strong consistency model = All access attempts (e.g. parallel) to a particular item return the same unique state. Old\stale data reads are avoided, but it will cost you more.
Good information to know for any AWS certification tests…. 🙂
DevOps Unleashed 