On the Semantics of Snapshot Isolation

Raad, Azalea; Lahav, Ori; Vafeiadis, Viktor

doi:10.1007/978-3-030-11245-5_1

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…The consistency models in this paper were studied in several recent works [21,20,25,43,16,44,14]. Most of them focused on their operational and axiomatic formalizations.…”

Section: Related Workmentioning

confidence: 99%

Checking Robustness Between Weak Transactional Consistency Models

Bouajjani

Enea

2021

Programming Languages and Systems

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Concurrent accesses to databases are typically encapsulated in transactions in order to enable isolation from other concurrent computations and resilience to failures. Modern databases provide transactions with various semantics corresponding to different trade-offs between consistency and availability. Since a weaker consistency model provides better performance, an important issue is investigating the weakest level of consistency needed by a given program (to satisfy its specification). As a way of dealing with this issue, we investigate the problem of checking whether a given program has the same set of behaviors when replacing a consistency model with a weaker one. This property known as robustness generally implies that any specification of the program is preserved when weakening the consistency. We focus on the robustness problem for consistency models which are weaker than standard serializability, namely, causal consistency, prefix consistency, and snapshot isolation. We show that checking robustness between these models is polynomial time reducible to a state reachability problem under serializability. We use this reduction to also derive a pragmatic proof technique based on Lipton’s reduction theory that allows to prove programs robust. We have applied our techniques to several challenging applications drawn from the literature of distributed systems and databases.

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“…The consistency models in this paper were studied in several recent works [21,20,25,43,16,44,14]. Most of them focused on their operational and axiomatic formalizations.…”

Section: Related Workmentioning

confidence: 99%

Checking Robustness Between Weak Transactional Consistency Models

Bouajjani

Enea

2021

Programming Languages and Systems

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“…The (ser1) and (ser2) axioms are those of serialisability [Papadimitriou 1979] adapted to our declarative framework as done e.g. in [Raad et al , 2019. The (ser1) ensures that e.g.…”

Section: The Persistent Serialisability Model (Pser)mentioning

confidence: 99%

Weak persistency semantics from the ground up: formalising the persistency semantics of ARMv8 and transactional models

Raad

Wickerson

Vafeiadis

2019

Proc. ACM Program. Lang.

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Emerging non-volatile memory (NVM) technologies promise the durability of disks with the performance of volatile memory (RAM). To describe the persistency guarantees of NVM, several memory persistency models have been proposed in the literature. However, the formal persistency semantics of mainstream hardware is unexplored to date. To close this gap, we present a formal declarative framework for describing concurrency models in the NVM context, and then develop the PARMv8 persistency model as an instance of our framework, formalising the persistency semantics of the ARMv8 architecture for the first time. To facilitate correct persistent programming, we study transactions as a simple abstraction for concurrency and persistency control. We thus develop the PSER (persistent serialisability) persistency model, formalising transactional semantics in the NVM context for the first time, and demonstrate that PSER correctly compiles to PARMv8. This then enables programmers to write correct, concurrent and persistent programs, without having to understand the low-level architecture-specific persistency semantics of the underlying hardware. CCS Concepts: • Theory of computation → Concurrency; Semantics and reasoning; • Software and its engineering → General programming languages.

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Intel PMDK Transactions: Specification, Validation and Concurrency

Raad,

Lahav,

Wickerson

et al. 2024

Lecture Notes in Computer Science

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Software Transactional Memory (STM) is an extensively studied paradigm that provides an easy-to-use mechanism for thread safety and concurrency control. With the recent advent of byte-addressable persistent memory, a natural question to ask is whether STM systems can be adapted to support failure atomicity. In this paper, we answer this question by showing how STM can be easily integrated with Intel’s Persistent Memory Development Kit (PMDK) transactional library (which we refer to as txPMDK) to obtain STM systems that are both concurrent and persistent. We demonstrate this approach using known STM systems, TML and NOrec, which when combined with txPMDK result in persistent STM systems, referred to as PMDK-TML and PMDK-NORec, respectively. However, it turns out that existing correctness criteria are insufficient for specifying the behaviour of txPMDK and our concurrent extensions. We therefore develop a new correctness criterion, dynamic durable opacity, that extends the previously defined notion of durable opacity with dynamic memory allocation. We provide a model of txPMDK, then show that this model satisfies dynamic durable opacity. Moreover, dynamic durable opacity supports concurrent transactions, thus we also use it to show correctness of both PMDK-TML and PMDK-NORec.

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On the Semantics of Snapshot Isolation

Cited by 5 publications

References 24 publications

Checking Robustness Between Weak Transactional Consistency Models

Checking Robustness Between Weak Transactional Consistency Models

Weak persistency semantics from the ground up: formalising the persistency semantics of ARMv8 and transactional models

Intel PMDK Transactions: Specification, Validation and Concurrency

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