How the row cache affects reads

A brief description about how the row cache affects reads.

Typical of any database, reads are fastest when the most in-demand data (or hot working set) fits into memory. Although all modern storage systems rely on some form of caching to allow for fast access to hot data, not all of them degrade gracefully when the cache capacity is exceeded and disk I/O is required. Cassandra's read performance benefits from built-in caching. For rows that are accessed frequently, Cassandra has a built-in key cache and an optional row cache.