Conflict Detection Tradeoffs for Replicated Data
Carey, Michael J
University of Wisconsin-Madison Department of Computer Sciences
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Many concurrency control algorithms have been proposed for use in distributed database systems. Despite the large number of available algorithms, and the fact that distributed database systems are becoming a commercial reality, distributed concurrency control performance tradeoffs are still not well understood. In this paper we examine some of these tradeoffs by using a detailed model of a distributed DBMS to study a set of representative algorithms, including several derivatives of the two-phase locking, timestamp ordering, and optimistic approaches to distributed concurrency control. In particular, we examine the performance of these algorithms as a function of data contention for various levels of data replication and �distributedness� of accesses to replicated data. The results provide some interesting insights into how the tradeoffs between early and late conflict detection vary as a function of message cost, and should prove useful to distributed database system designers.