According to the benchmarks, Redka is several times slower than Redis. Still, it can do up to 100K op/sec on a Macbook Air, which is pretty good if you ask me (and probably 10x more than most applications will ever need). Redka stores data in a SQLite database with a simple schema and provides views for better introspection. fyi
Sometimes, we read and write more than decades data in one request. And should sort or search data at same time. So a memory cach should have a very throttle.