In a replicated database system, the quorum consensus scheme is a well-known replication control protocol which ensures data consistency despite of network partitioning as well as site failures. There have been considerable efforts to reduce the cost of quorum consensus systems. Most of them attempt to reduce the size of quorums by imposing a logical structure, e.g. tree, grid, on the copy sites for minimizing the cost.
In this paper, we propose a different scheme which reduces the cost of message exchange in quorum consensus systems. It combines some quorum acquisition messaging steps which are originally performed before each operation of a transaction. This method has both advantage and disadvantage from the viewpoint of entire system performance. It could facilitate performance by reducing the messaging steps and the number of messages. However, it could also have an undesirable effect on the performance due to the increased lock duration time.
Hence, our proposed method clusters operations of a transaction to minimize loss and maximize profit. We show through performance experiments that our proposed scheme can improve the performance of quorum systems.
