Strongly consistent distributed systems are easy to reason about but face fundamental limitations in availability and performance. Weakly consistent systems can be implemented with very high performance but place a burden on the application developer to reason about complex interleavings of execution. Invariant confluence provides a formal framework for understanding when we can get the best of both worlds. An invariant confluent object can be efficiently replicated with no coordination needed to preserve its invariants. However, actually determining whether or not an object is invariant confluent is challenging. In this paper, we establish conditions under which a commonly used sufficient condition for invariant confluence is both necessary and sufficient, and we use this condition to design a general-purpose interactive invariant confluence decision procedure. We then take a step beyond invariant confluence and introduce a generalization of invariant confluence, called segmented invariant confluence, that allows us to replicate non-invariant confluent objects with a small amount of coordination. We implement these formalisms in a prototype called Lucy and find that our decision procedures efficiently handle common real-world workloads including foreign keys, escrow transactions, and more.

中文翻译：

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检查不变的汇合，整体或部分

高度一致的分布式系统很容易推理，但在可用性和性能方面面临着根本的限制。弱一致性系统可以以非常高的性能实现，但会给应用程序开发人员带来负担，以推理复杂的执行交错​​。不变的汇合提供了一个正式的框架来理解我们什么时候可以两全其美。一个不变的融合对象可以被有效地复制，而无需协调来保持其不变性。然而，实际上确定一个对象是否是不变的汇合是具有挑战性的。在本文中，我们建立了一个常用的不变汇合充分条件既是必要条件又是充分条件的条件，我们利用这个条件设计了一个通用的交互式不变汇合决策过程。然后，我们超越了不变汇合，并引入了不变汇合的推广，称为分段不变汇合，它允许我们以少量协调复制非不变汇合对象。我们在一个名为 Lucy 的原型中实现了这些形式，并发现我们的决策程序可以有效地处理常见的现实世界工作负载，包括外键、托管交易等。