The author also has thoughts on Datomic: http://www.xaprb.com/blog/2013/12/28/immutability-mvcc-and-garbage-collection/ http://www.xaprb.com/blog/2013/12/28/imm

The author also has thoughts on Datomic: http://www.xaprb.com/blog/2013/12/28/immutability-mvcc-and-garbage-collection/ http://www.xaprb.com/blog/2013/12/28/immutability-mvcc-and-g... tl;dr; append-only is great as long as you don't use your database much.