IEEE Access (Jan 2021)

The Logical Timestamp Skew Anomaly in Event-Replicated Transaction Schedulers

  • Emil Koutanov

DOI
https://doi.org/10.1109/ACCESS.2021.3107506
Journal volume & issue
Vol. 9
pp. 123375 – 123397

Abstract

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To sidestep reasoning about the complex effects of concurrent execution, many system designers have conveniently embraced strict serializability on the strength of its claims, support from commercial and open-source database communities and ubiquitous levels of industry adoption. Crucially, distributed components are built on this model; multiple schedulers are composed in an event-driven architecture to form larger, ostensibly correct systems. This paper examines the oft-misconstrued position of strict serializability as a composable correctness criterion in the design of such systems. An anomaly is presented wherein a strict serializable scheduler in one system produces a history that cannot be serially applied to even a weak prefix-consistent replica in logical timestamp order. Several solutions are presented under varying isolation properties, including novel isolation properties contributed by this paper. It is further shown that every nondeterministic scheduler is anomaly-prone, every nonconcurrent scheduler is anomaly-free, and at least one deterministic concurrent scheduler is anomaly-free.

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