[infinispan-dev] The "Triangle" pattern for reducing Put latency

At our last face to face meeting we were discussing about possible strategies to reduce the latency of a Put operation. I wasn't part of that conversation, but see in our notes that the idea would be to have the Originator to wait for first ACK from a backup, rather than having the backups confirm with the Owner first, although this would need for Gets to have to go to the primary owner exclusively to keep the current consistency semantics. An alternative is to wait for all ACKs, but I think this could still be optimised in "triangle shape" too by having the Originator only wait for the ACKs from the non-primary replicas? So backup owners have to send a confirmation message to the Originator, while the Primary owner isn't expecting to do so. I suspect the tricky part is what happens when the Primary owner rules +1 to apply the change, but then the backup owners (all or some of them) somehow fail before letting the Originator know. The Originator in this case should seek confirmation about its operation state (success?) with the Primary owner; this implies that the Primary owner needs to keep track of what it's applied and track failures too, and this log needs to be pruned. Sounds pretty nice, or am I missing other difficulties? Thanks, Sanne