Cache vs. Database: How Architecture Impacts Performance

The article explores the architectural differences and performance implications of using Memcached as a caching system compared to ScyllaDB, a persistent database with caching capabilities. The author, alongside Memcached maintainer Alan Kasindorf, conducted benchmarks to assess how each system uses memory, handles various data models, and manages disk I/O. Memcached is highlighted for its efficiency with in-memory caching and pipelined requests, allowing higher throughput and scalability, especially with smaller payloads, while ScyllaDB supports complex data models and persistent storage, albeit with higher memory overhead. The tests revealed that Memcached's Extstore can store more items on disk, albeit with manual tuning, whereas ScyllaDB offers robust data persistence and high-performance disk I/O operations. The choice between the two depends on specific workload requirements, such as data model complexity and the need for data persistence, as each system comes with unique strengths and trade-offs that impact performance testing and operational efficiency.