《2pc_paper》.pdf

Transaction Management in the R* Distributed Database Management System C. MOHAN, B. LINDSAY, and R. OBERMARCK IBM Almaden Research Center This paper deals with the transaction management aspects of the R* distributed database system. It concentrates primarily on the description of the R* commit protocols, Presumed Abort (PA) and Presumed Commit (PC). PA and PC are extensions of the well-known, two-phase (2P) commit protocol. PA is optimized for read-only transactions and a class of multisite update transactions, and PC is optimized for other classes of multisite update transactions. The optimizations result in reduced intersite message traffic and log writes, and, consequently, a better response time. The paper also discusses R*‘s approach toward distributed deadlock detection and resolution. Categories and Subject Descriptors: C.2.4 [Computer-Communication Networks]: Distributed Systems-distributed datahes; D.4.1 [Operating Systems]: Process Management-concurrency; deadlocks, syndvonization; D.4.7 [Operating Systems]: Organization and Design-distributed sys- tems; D.4.5 [Operating Systems]: Reliability--fault tolerance; H.2.0 [Database Management]: General-concurrency control; H.2.2 [Database Management]: ‘Physical Design-recouery and restart; H.2.4 [Database Management]: Systems-ditributed systems; transactionprocessing; H.2.7 [Database Management]: Database Administration-logging and recouery General Terms: Algorithms, Design, Reliability Additional Key Words and Phrases: Commit protocols, deadlock victim selection 1. INTRODUCTION