Distributed Consistency Beyond Queries

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Programming asynchronous distributed systems is a challenging task in which consistency is often achieved by use of expensive coordination protocols like Paxos and 2PC. The CALM theorem, first conjectured by Hellerstein, is one of the first results to challenge this practice by stating that a problem can have a consistent, coordination-free distributed implementation if (and only if) the problem is monotonic. This result was proven for queries and shown to extend beyond monotonic (yet monotonic-like) queries for data systems having specific knowledge about the partitioning of data over the network. In this article, we extend the latter results in several ways. We consider problems that can be modeled as mappings from distributed instances to distributed instances, enabling insights into a much broader range of problems than queries. Furthermore, our model can express arbitrary system configurations, allowing us to reason about the expressiveness of any particular distributed system and thereby revealing a nuanced gradient of problems with increasing coordination-needs. Finally, we apply our model to a recent question about the expressiveness of coordination-free queries, raised by Hellerstein and Alvaro.
Original languageEnglish
Title of host publicationPODS '23: Proceedings of the 42nd ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems
Number of pages12
ISBN (Electronic)9798400701276
Publication statusPublished - 18 Jun 2023
Event42nd ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems - Seattle, United States
Duration: 18 Jun 202323 Jun 2023
Conference number: 42

Publication series

NameProceedings of the ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems


Conference42nd ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems
Abbreviated titlePODS 2023
Country/TerritoryUnited States
Internet address

Bibliographical note

Funding Information:
This work is partly funded by FWO-grant G062721N.

Publisher Copyright:
© 2023 ACM.

Copyright 2023 Elsevier B.V., All rights reserved.


  • relational transducer
  • distributed database
  • coordination
  • consistency
  • computability

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