> The only reason for a KV cache is if you're running a slow language like Ruby, PHP, Python, where the memory overhead for objects is large and the speed of a

> The only reason for a KV cache is if you're running a slow language like Ruby, PHP, Python, where the memory overhead for objects is large and the speed of a remote cache is roughly the same as one in memory. If you find yourself needing a cache for good enough performance you shouldn't be using these languages in the first place. In memory caches don't work well when you need 100+ server instances to handle the load anyways You're saying reading a serialized Python object from Redis and deserializing it is comparable to accessing a ready in-memory object? No, it's an order of magnitude slower. I think the reason in-memory caches are not used much in Python/Ruby is a concurrency model, ie. in Python/Ruby you usually have to run multiple processes and in Java you run multiple threads, so the in-memory cache can be just a regular data structure normally accessed. Also, I think you are overestimating the Python's memory overhead compared to Java - Python's int is 24 bytes and Java's Integer is 16 bytes (and using PyPy is another story - it can use several times less memory compared to Java).