Abstract

 
 
 Given a distributed system with several shared objects and many processes concurrently updating and reading them, it is convenient that the system achieves convergence on the value of these objects. Such property can be guaranteed depending on the consistency model being employed. Causal Consistency is a weak consistency model that is easy and cheap to implement. However, due to the lack of real-time considerations, this model cannot offer convergence. A solution for overcoming that problem is to include time aspects within the framework of the model. This is the aim of Timed Causal Consistency.
 
 
Highlights
A distributed application is build up from processes executed at different nodes from possibly distant locations
Proof At most ∆ units of time after the last write for every shared object, Timed Causal Consistency (TCC) guarantees that the updated value is known to every site in the distributed system, we can insert a convergent cut over each shared object ∆ units of time after the corresponding last write operation, which according to Definition 11 proves that the execution satisfies absolute convergence
The causal consistency model gives a weakening of sequential consistency, making a difference between events that are potentially causally related and those that are not
Summary
A distributed application is build up from processes executed at different nodes from possibly distant locations. Definition 3 History H satisfies Causal Consistency (CC) if for each site i there is a serialization Si of the set Hi+w that respects causal order “→” [2]. Timed consistency (TC) as proposed in [15] requires that if the effective time of a write is t, the value written by this operation must be visible to all sites in the distributed system by time t + ∆, where ∆ is a parameter of the execution. Up to the second operation of Site 1, the execution satisfies TC for the value of ∆ presented in this figure, but, by that same instant, LIN is no longer satisfied After this point, the execution is not even timed because there are read operations in Site 1 that start more than ∆ units of real-time after Site 0 writes the value 7 into object X and these read operations do not return this value
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
