Currently, the entire keyspace is queried, but querying the entire keyspace does not requiring touching every partition. Only a covering subset which is influen

Currently, the entire keyspace is queried, but querying the entire keyspace does not requiring touching every partition. Only a covering subset which is influenced by your N-value (number of replicas) needs to be queried because the index is replicated alongside your k/v data. For example, in a 4-partition ring with N=2, keys mapping to p1 are replicated on p1,p2; p2 on p2,p3; p3 on p3,p4; and p4 on p4,p1. As such, you only need to query p1,p3 or p2,p4 to cover the entire keyspace. In general, approximately RingSize / N partitions need to be queried. The new smart coverage code figures this out as well as deals with routing around failed nodes and other issues. EDIT: Since the replicas value (N) is settable per bucket in Riak, there's some interesting extreme cases that you could envision here. For example, you could have a bucket where N = RingSize, in which case the index is replicated to every node and you only need to query a single partition to lookup values. Of course, then you lose the ability to perform multiple queries in parallel with a more partitioned/distributed index space (which would be more useful for large results sets). As with database systems in general, the best configuration here depends on data and use case.