A Fault-Tolerant Commit Protocol for Replicated Databases

When failures occur during the execution of distributed commit protocols, the protocols may block in some partitions to avoid inconsistent termination of the transaction, thus making data items in these partitions unavailable for accesses. We present a protocol that incorporates two new ideas with the goal of improving data availability. First, a new two-level voting scheme is proposed for deciding in which partitions to terminate the transaction. In this scheme, a choice is made based on the number of data items available in the partition rather than on the number of individual nodes. Indeed, in replicated systems, a criterion based on the number of nodes may be misleading. Second, we propose a way to reduce blocking caused by accumulating network fragmentation. The idea employs the views mechanism previously used in replica management. 1 Introduction The notion of a transaction [1] has proven to be a convenient general abstraction for data manipulation in the presence of failures, es..