Berkeley Workshop 

Abstract: This paper contains algorithms for ensuring the consistency of a distributed relational data base subject to multiple, concurrent updates. Also included are mechanisms to correctly update multiple copies of objects and to continue operation when less than all machines in the network are operational. Together with [4] and [12], this paper constitutes the significant portions of the design for a distributed data base version of INGRES.

Abstract: Herein, we propose a commit protocol and an associated recovery protocol that is resilient to site failures, lost messages, and network partitioning. The protocols do not require that a failure be correctly identified or even detected. The only potential effect of undetected failures is a degradation in performance. The protocols use a weighted voting scheme that supports an arbitrary degree of data replication (including none) and allows unilaterally aborts by any site. This last property facilitates the integration of these protocols with concurrency control protocols. Both protocols are centralized protocols with low message overhead.