Introducing Netflix’s Key-Value Data Abstraction Layer
At Netflix our ability to deliver seamless, high-quality, streaming experiences to millions of users hinges on robust, global backend infrastructure. Central to this infrastructure is our use of multiple online distributed databases such as Apache Cassandra, a NoSQL database known for its high availability and scalability. Cassandra serves as the backbone for a diverse array of use cases within Netflix, ranging from user sign-ups and storing viewing histories to supporting real-time analytics and live streaming.
Over time as new key-value databases were introduced and service owners launched new use cases, we encountered numerous challenges with datastore misuse. Firstly, developers struggled to reason about consistency, durability and performance in this complex global deployment across multiple stores. Second, developers had to constantly re-learn new data modeling practices and common yet critical data access patterns. These include challenges with tail latency and idempotency, managing “wide” partitions with many rows, handling single large “fat” columns, and slow response pagination. Additionally, the tight coupling with multiple native database APIs — APIs that continually evolve and sometimes introduce backward-incompatible changes — resulted in org-wide engineering efforts to maintain and optimize our microservice’s data access.
To overcome these challenges, we developed a holistic approach that builds upon our Data Gateway Platform. This approach led to the creation of several foundational abstraction services, the most mature of which is our Key-Value (KV) Data Abstraction Layer (DAL). This abstraction simplifies data access, enhances the reliability of our infrastructure, and enables us to support the broad spectrum of use cases that Netflix demands with minimal developer effort.
