Recovery and Performance of Atomic Commit Processing in Distributed Database Systems

A transaction is traditionally deened so as to provide the properties of atomicity, consistency, integrity, and durability (ACID) for any operation it performs. In order to ensure the atomicity of distributed transactions, an atomic commitprotocol needs to be followed by all sites participating in a transaction execution to agree on the nal outcome, that is, commit or abort. A variety of commit protocols have been proposed that either enhance the performance of the classical two-phase commit protocol during normal processing or reduce the cost of recovery processing after a failure. In this chapter, we survey a number of two-phase commit variants and optimizations, including some recent ones, providing an insight in the performance trade-oo between normal and recovery processing. We also analyze the performance of a representative set of commit protocols both analytically as well as empirically using simulation. 13.1 INTRODUCTION Transactions are powerful abstractions that facilitate the structuring of database systems, and distributed systems in general, in a reliable manner. Each transaction represents a task or a logical function that involves access to a shared database and 370