Lecture 16: Cache Consistency: Memcached at Facebook

The podcast analyzes Facebook's use of Memcached to manage high traffic loads, highlighting the trade-offs between performance and consistency. It explores the evolution of web architectures, from single-machine setups to sharded databases and caching layers, emphasizing Memcached's role in improving read speeds. The discussion covers Facebook's multi-data center approach, the use of replication and partitioning, and strategies for handling hot keys and in-cast congestion. The podcast also examines consistency challenges, such as stale data and update races, and explains Facebook's lease mechanism for addressing the thundering herd problem and ensuring data freshness. Ultimately, caching is vital to conceal almost all the load from the database servers.