Message rearrange theory in message recovery protocol

In optimistic message protocols, the receiving order of not logged messages and their payloads may be lost because of process failures. To address the lost order of received but not logged messages, our paper proposes a message rearranging theory with improved logic clock. With improved logic clock, our protocol rearranges lost messages as an equivalent message receiving sequence on the assumption of PWD. Once process failures occur, our recovery protocol first determines the lost messages with message number check theory and then restores them by logging files. Then the recovery protocol rearranges those lost messages, forms an equivalent message sequence and replaces the original one during failure-free process execution. There are two main advantages of our protocol: first only failed processes rollback and not failed processes can ongoing; second our protocol can deal with more than one failure.