Abstract | ||
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Herlihyu0027s consensus hierarchy ranks the power of various synchronization primitives for solving consensus in a model where asynchronous processes communicate through shared memory and fail by halting. This paper revisits the consensus hierarchy in a model with crash-recovery failures, where the specification of consensus, called emph{recoverable consensus} in this paper, is weakened by allowing non-terminating executions when a process fails infinitely often. Two variations of this model are considered: independent failures, and simultaneous (i.e., system-wide) failures. Several results are proved in this model: (i) We prove that any primitive at level two of Herlihyu0027s hierarchy remains at level two if simultaneous crash-recovery failures are introduced. This is accomplished by transforming (one instance of) any 2-process conventional consensus algorithm to a 2-process recoverable consensus algorithm. (ii) For any $n u003e 1$ and $f u003e 0$, we show how to use $f+1$ instances of any conventional $n$-process consensus algorithm and $Theta(f + n)$ read/write registers to solve $n$-process recoverable consensus when crash-recovery failures are independent, assuming that every execution contains at most $f$ such failures. (iii) Next, we prove for any $f u003e 0$ that any 2-process recoverable consensus algorithm that uses TAS and read/writer registers requires at least $f+1$ TAS objects, assuming that crash-recovery failures are independent and every execution contains at most $f$ such failures. (iv) Lastly, we generalize and strengthen (iii) by proving that any universal construction of $n$-process recoverable consensus from a type $T$ with consensus number $n$ and read/write registers requires at least $f+1$ base objects of type $T$ in executions with up to $f$ failures. |
Year | Venue | Field |
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2018 | arXiv: Distributed, Parallel, and Cluster Computing | Asynchronous communication,Consensus algorithm,Synchronization,Shared memory,Computer science,Theoretical computer science,Hierarchy,Distributed computing |
DocType | Volume | Citations |
Journal | abs/1804.10597 | 0 |
PageRank | References | Authors |
0.34 | 0 | 1 |
Name | Order | Citations | PageRank |
---|---|---|---|
Wojciech Golab | 1 | 210 | 17.22 |