Distributed data flow

An illustration of the basic concepts involved in the definition of a distributed data flow.

Distributed data flow (also abbreviated as distributed flow) refers to a set of events in a distributed application or protocol.

Distributed data flows serve a purpose analogous to variables or method parameters in programming languages such as Java, in that they can represent state that is stored or communicated by a layer of software. Unlike variables or parameters, which represent a unit of state that resides in a single location, distributed flows are dynamic and distributed: they simultaneously appear in multiple locations within the network at the same time. As such, distributed flows are a more natural way of modeling the semantics and inner workings of certain classes of distributed systems. In particular, the distributed data flow abstraction has been used as a convenient way of expressing the high-level logical relationships between parts of distributed protocols.[1][2][3]

Informal properties

A distributed data flow satisfies the following informal properties.

Formal representation

Formally, we represent each event in a distributed flow as a quadruple of the form (x,t,k,v), where x is the location (e.g., the network address of a physical node) at which the event occurs, t is the time at which this happens, k is a version, or a sequence number identifying the particular event, and v is a value that represents the event payload (e.g., all the arguments passed in a method call). Each distributed flow is a (possibly infinite) set of such quadruples that satisfies the following three formal properties.

In addition to the above, flows can have a number of additional properties.

References

  1. ↑ Ostrowski, K., Birman, K., Dolev, D., and Sakoda, C. (2009). "Implementing Reliable Event Streams in Large Systems via Distributed Data Flows and Recursive Delegation", 3rd ACM International Conference on Distributed Event-Based Systems (DEBS 2009), Nashville, TN, USA, July 6–9, 2009, http://www.cs.cornell.edu/~krzys/krzys_debs2009.pdf
  2. ↑ Ostrowski, K., Birman, K., and Dolev, D. (2009). "Distributed Data Flow Language for Multi-Party Protocols", 5th ACM SIGOPS Workshop on Programming Languages and Operating Systems (PLOS 2009), Big Sky, MT, USA. October 11, 2009, http://www.cs.cornell.edu/~krzys/krzys_plos2009.pdf
  3. ↑ Ostrowski, K., Birman, K., Dolev, D. (2009). "Programming Live Distributed Objects with Distributed Data Flows", Submitted to the International Conference on Object Oriented Programming, Systems, Languages and Applications (OOPSLA 2009), http://www.cs.cornell.edu/~krzys/krzys_oopsla2009.pdf
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