~10X a performance penalty doesn't seem that bad. In C a pointer derefference will beat a web service call by more than 10X. Also why a handjammed KV store? EDN and other(faster) serialization libraries have been around for quite a while.
I used nippy originally, then later Java serialization libraries once it became clear optimization was required. I tried using both Redis and RocksDB. The happy case had all but the last layer of nodes sitting in cache in memory (as long as your memory is more than 1/32 of the size of your disk).
I think I could do better starting from scratch given what I've learned.
