Transactions and Scalability in Cloud Databases—Can’t We Have Both?

NoSQL cloud database services, like Amazon DynamoDB, are popular for their simple key-value operations, unbounded scalability and predictable low-latency. Atomic transactions, while popular in relational databases, carry the specter of complexity and low performance, especially when used for workloads with high contention. Transactions often have been viewed as inherently incompatible with NoSQL stores, and the few commercial services that combine both come with limitations. This talk examines the tension between transactions and non-relational databases, and it recounts my journey of adding transactions to DynamoDB. I conclude that atomic transactions with full ACID properties can be supported without unduly compromising on performance, availability, self-management, or scalability.