Remove-Win: a Design Framework for Conflict-free Replicated Data Types

Zhang, Yuqi; Wei, Hengfeng; Huang, Yu

doi:10.1109/icpads53394.2021.00081

Cited by 3 publications

(12 citation statements)

References 8 publications

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“…For example when developing the Rwf-List [53], we find violations of eventual consistency through stress testing in a small number of experiments, as shown in Issue #1 below.…”

Section: Whymentioning

confidence: 95%

“…The details of these strategies are irrelevant to our discussions on the Met framework here. More details of these CRDTs can be found in [53].…”

Section: Our Experiences Motivating Metmentioning

confidence: 99%

“…If no bug is found after 24 hours of stress testing, the implementation is deemed (sufficiently) correct. More details of the CRDT development can be found in our previous work [53]. The experiences in testing our CRDT implementations extensively motivate us to design the Met framework, as detailed below.…”

Section: Our Experiences Motivating Metmentioning

confidence: 99%

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MET: Model Checking-Driven Explorative Testing of CRDT Designs and Implementations

Zhang¹,

Huang²,

Wei³

et al. 2022

Preprint

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“…For example when developing the Rwf-List [53], we find violations of eventual consistency through stress testing in a small number of experiments, as shown in Issue #1 below.…”

Section: Whymentioning

confidence: 95%

“…The details of these strategies are irrelevant to our discussions on the Met framework here. More details of these CRDTs can be found in [53].…”

Section: Our Experiences Motivating Metmentioning

confidence: 99%

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MET: Model Checking-Driven Explorative Testing of CRDT Designs and Implementations

Zhang¹,

Huang²,

Wei³

et al. 2022

Preprint

Self Cite

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“…CRDT-Redis currently provides two container types Redis-set and Redis-priority-queue (Redis-PQ in short). Each data type is designed with different conflict-resolution strategies: add-win (A in short), remove-win (R in short), and the Rwf framework (F in short) [27]. Data types with different conflict-resolve strategies are denoted Set-A, Set-R, Set-F, PQ-A, PQ-R, and PQ-F.…”

Section: Experiments Setupmentioning

confidence: 99%

“…We reproduce the experiments in our previous work on CRDT design based on CRDT-Redis [27]. We set 1000 checkpoints for the replicas in the experiments where there are about 100,000 operations in the workload and the number of operations per second is bounded by 3000.…”

Section: Experiments Designmentioning

confidence: 99%

ViSearch: Weak Consistency Measurement for Replicated Data Types

Shi¹,

Zhang²,

Huang³

et al. 2022

Preprint

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Large-scale replicated data type stores often resort to eventual consistency to guarantee low latency and high availability. It is widely accepted that programming over eventually consistent data stores is challenging, since arbitrary divergence among replicas is allowed. Moreover, pragmatic protocols actually achieve consistency guarantees stronger than eventual consistency, which can be and need to be utilized to facilitate the reasoning of and programming over replicated data types. Toward the challenges above, we propose the ViSearch framework for precise measurement of eventual consistency semantics. ViSearch employs the visibilityarbitration specification methodology in concurrent programming, which extends the linearizability-based specification methodology with a dynamic visibility relation among operations, in addition to the standard dynamic happen-before and linearization relations. The consistency measurement using ViSearch is NP-hard in general. To enable practical and efficient consistency measurement in replicated data type stores, the ViSearch framework refactors the existing brute-force checking algorithm to a generic algorithm skeleton, which further enables efficient pruning of the search space and effective parallelization. We employ the ViSearch framework for consistency measurement in two replicated data type stores Riak and CRDT-Redis. The experimental evaluation shows the usefulness and cost-effectiveness of consistency measurement based on the ViSearch framework in realistic scenarios.

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Model‐checking‐driven explorative testing of CRDT designs and implementations

Zhang

Huang

Wei

et al. 2023

J Software Evolu Process

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Internet‐scale distributed systems often replicate data at multiple geographic locations to provide low latency and high availability, despite node and network failures. According to the CAP theorem, low latency and high availability can only be achieved at the cost of accepting weak consistency. The conflict‐free replicated data type (CRDT) is a framework that provides a principled approach to maintaining eventual consistency among data replicas. CRDTs have been notoriously difficult to design and implement correctly. Subtle deep bugs lie in the complex and tedious handling of all possible cases of conflicting data updates. We argue that the CRDT design should be formally specified and model checked, to uncover deep bugs which are beyond human reasoning. The implementation further needs to be systematically tested. On the one hand, the testing needs to inherit the exhaustive nature of the model checking and ensures the coverage of testing. On the other hand, the testing is expected to find coding errors which cannot be detected by design level verification. Toward the challenges above, we propose the model‐checking‐driven explorative testing (MET) framework. At the design level, MET uses TLA+ to specify and model check CRDT designs. At the implementation level, MET conducts model‐checking‐driven explorative testing, in the sense that the test cases are automatically generated from the model‐checking traces. The system execution is controlled to proceed deterministically, following the model‐checking trace. The explorative testing systematically controls and permutes all nondeterministic choices of message reorderings. We apply MET in our practical development of CRDTs. The bugs in both designs and implementations of CRDTs are found. As for bugs which can be found by traditional testing techniques, MET greatly reduces the cost of fixing the bugs. Moreover, MET can find subtle deep bugs which cannot be found by existing techniques at a reasonable cost. Based on our practical use of MET, we discuss how MET provides us with sufficient confidence in the correctness of our CRDT designs and implementations.Conflict‐free replicated data type (CRDT) is a framework that provides a principled approach to maintaining eventual consistency among data replicas in distributed systems. CRDTs have been notoriously difficult to design and implement correctly. We propose model‐checking‐driven explorative testing (MET) framework for dealing with such problem. We apply MET in our practical development of CRDTs. MET successfully finds subtle deep bugs and provides us with sufficient confidence in the correctness of our CRDT designs and implementations.

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Remove-Win: a Design Framework for Conflict-free Replicated Data Types

Cited by 3 publications

References 8 publications

MET: Model Checking-Driven Explorative Testing of CRDT Designs and Implementations

MET: Model Checking-Driven Explorative Testing of CRDT Designs and Implementations

ViSearch: Weak Consistency Measurement for Replicated Data Types

Model‐checking‐driven explorative testing of CRDT designs and implementations

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