4.1: Overview

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Page ID: 58515

Jerome H. Saltzer & M. Frans Kaashoek
Massachusetts Institute of Technology via MIT OpenCourseWare

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The previous chapter developed all-or-nothing atomicity and before-or-after atomicity, two properties that define a transaction. This chapter introduces or revisits several applications that can make use of transactions. Section 4.2 introduces constraints and discusses how transactions can be used to maintain invariants and implement memory models that provide interface consistency. Sections 4.3 and 4.4 develop techniques used in two different application areas, caching and geographically distributed replication, to achieve higher performance and greater durability, respectively. Section 4.5 discusses reconciliation, which is a way of restoring the constraint that replicas be identical if their contents should drift apart. Finally, Section 4.6 considers some perspectives relating to Chapters 3 and 4.