Reachability-based coordination for cyclic dataflow

Various embodiments provide techniques for working with large-scale collections of data pertaining to real world systems, such as a social network, a roadmap/GPS system, etc. The techniques perform incremental, iterative, and interactive parallel computation using a coordination clock protocol, which applies to scheduling computations and managing resources such as memory and network resources, in cyclic graphs including those resulting from a differential dataflow model that performs computations on differences in the collections of data.