Current triangle algorithm uses regular message (FIFO ordered) between the primary owner and backup owners of a key. While it ensures that the backup owners receives the stream of updates in the same order, it makes everything slower since it doesn't allow different keys to be handled in parallel.

"Triangle unordered" solves this problem by sending OOB messages (not ordered) between the primary and backup. To keep the consistency, Infinispan introduces the TriangleOrderManager that orders the updates based on the segment of the key.

While it is not as perfect as ordering per key, the segments are static; this removes the complexity and avoids handling the cluster topology changes and key adding/removal while improves the performance.