Hello dev@, We'd like to propose CEP-45: Mutation Tracking for adoption by the community. CEP-45 proposes adding a replication mechanism to track and reconcile individual mutations, as well as processes to actively reconcile missing mutations.
For keyspaces with mutation tracking enabled, the immediate benefits of this CEP are: * reduced replication lag with a continuous background reconciliation process * eliminate the disk load caused by repair merkle tree calculation * eliminate repair overstreaming * reduce disk load of reads on cluster to close to 1/CL * fix longstanding mutation atomicity issues caused by read repair and short read protection Additionally, although it's outside the scope of this CEP, mutation tracking would enable: * completion of witness replicas / transient replication, making the feature usable for all workloads * lightweight witness only datacenters The CEP is linked here: https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-45%3A+Mutation+Tracking, but please keep the discussion on the dev list. Thanks! Blake Eggleston
