I want to implement a cache system for our application, we've started integrating with Memcached. Recently I started hearing of Hypertable, and saw some great benchmarks done with that..
However, I couldn't find good comparison between the two.
Just to get things straight: I know that Hypertable is considered closer to a DB than to a cache. On the other hand, it's not exactly an RDBMS - in fact, it's exactly not an RDBMS. It has its own benefits, but the question is whether they're worth the performance cost (if any)?
Hypertable is an implementation of concepts in Google's BigTable. Namely a column-oriented DB which has properties of being highly denormalized which means it doesn't need joins.
Memcached is an in-memory caching layer which acts like a distributed hashtable, keeping your app from having to hit the actual DB.
Both lend themselves well to being distributed and work well with MapReduce style topologies but they serve different purposes. Memcached/DHT is going to serve to speed access to data in memory while HyperTable/BigTable are actual mechanisms for permanent data storage on disk.