Learning Apache Cassandra - Second Edition

Lightweight transactions

As discussed before, Cassandra provides eventual consistency rather than immediate consistency, which means data written will eventually be consistent across multiple replicas of the data. This has implications on the data returned by read queries. There is a possibility that reads could return stale data depending on how writes and reads are configured (the consistency levels at which both queries are performed). Strong consistency, which means reading the most recently written value, can be achieved using quorum reads and writes. But what if strong consistency is not enough? What if we have some operations to perform in sequence that must not be interrupted by others, that is, we must perform them one at a time, ...