THE PERFORMANCE OF 2 PHASE COMMIT PROTOCOLS IN THE PRESENCE OF SITE FAILURES

The two phase commit is an important protocol in distributed database systems. Much of the existing literature on the protocol is restricted to discussing and analyzing the protocol (and its variants) in the ab sence of Failures. Very little, especially in quantitative terms, has been written about its performance in the presence of site failures. I n this study, we use a simulation testbed of a distributed database sy stem to quantify the differences in the performances of four widely kn own variants of the 2PC protocols (the generic 2PC, presumed commit, p resumed abort, and early prepare). Our study covers both the no-failur e case and the case of site failures. We present a number of interesti ng results based on our experiments. One is that the performance of th ese protocols is highly dependent on the message-processing latency at the transaction coordinator site. Another is that the presumed abort protocol does not necessarily yield better performance in the presence of site failures.