Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing最新文献

{"title":"A certain freedom: thoughts on the CAP theorem","authors":"E. Brewer","doi":"10.1145/1835698.1835701","DOIUrl":"https://doi.org/10.1145/1835698.1835701","url":null,"abstract":"At PODC 2000, the CAP theorem received its first broad audience. Surprisingly for an impossibility result, one important effect has been to free designers to explore a wider range of distributed systems. Designers of wide-area systems, in which network partitions are considered inevitable, know they cannot have both availability and consistency, and thus can now justify weaker consistency. The rise of the \"NoSQL\" movement (\"Not Only SQL\") is an expression of this freedom. The choices of how and when to weaken consistency are often the defining characteristics of these systems, with new variations appearing every year. We review a variety of interesting places in the \"CAP Space\" as a way to illuminate these issues and their consequences. For example, automatic teller machines (ATMs), which predate the CAP theorem, surprisingly choose availability with weak consistency but with bounded risk. Finally, I explore a few of the options to try to \"work around\" the impossible. The most basic is the use of commutative operations, which make it easy to restore consistency after a partition heals. However, even many commutative operations have non-commutative exceptions in practice, which means that the exceptions may be incorrect or late. Adding the concept of \"delayed exceptions\" allows more operations to be considered commutative and simplifies eventual consistency during a partition. Furthermore, we can think of delayed exception handling as \"compensation\" - we execute a compensating transaction that restores consistency. Delayed exception handling with compensation appears to be what most real wide-area systems do - inconsistency due to limited communication is treated as an exception and some exceptional action, such as monetary compensation or even legal action, is used to fix it. This approach to wide-area systems puts the emphasis on audit trails and recovery rather than prevention, and implies that we should expand and formalize the role of compensation in the design of complex systems","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130512241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Session details: Regular papers","authors":"Antonio Fernandez Anta","doi":"10.1145/3258216","DOIUrl":"https://doi.org/10.1145/3258216","url":null,"abstract":"","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125260708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Session details: Regular papers","authors":"Seth Gilbert","doi":"10.1145/3258210","DOIUrl":"https://doi.org/10.1145/3258210","url":null,"abstract":"","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131562541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The multiplicative power of consensus numbers","authors":"Damien Imbs, M. Raynal","doi":"10.1145/1835698.1835705","DOIUrl":"https://doi.org/10.1145/1835698.1835705","url":null,"abstract":"The Borowsky-Gafni (BG) simulation algorithm is a powerful reduction algorithm that shows that t-resilience of decision tasks can be fully characterized in terms of wait-freedom. Said in another way, the BG simulation shows that the crucial parameter is not the number n of processes but the upper bound t on the number of processes that are allowed to crash. The BG algorithm considers colorless decision tasks in the base read/write shared memory model. (Colorless means that if, process decides a value, any other process is allowed to decide the very same value.) This paper considers system models made up of n processes prone to up to t crashes, and where the processes communicate by accessing read/write atomic registers (as assumed by the BG) and (differently from the BG) objects with consensus number x accessible by at most x processes (with x ≤ t < n). Let ASM(n,t,x) denote such a system model. While the BG simulation has shown that the models ASM(n,t,1) and ASM(t+1,t,1) are equivalent, this paper focuses the pair (t,x) of parameters of a system model. Its main result is the following: the system models ASM (n1,t1,x1) and ASM (n2,t2,x2) have the same computational power for colorless decision tasks if and only if ⌊t1⁄x1⌋ = ⌊t1⁄x1⌋. As can be seen, this contribution complements and extends the BG simulation. It shows that consensus numbers have a multiplicative power with respect to failures, namely the system models ASM(n,t',x) and ASM(n,t,1) are equivalent for colorless decision tasks iff (t x x) ≤ t' ≤ (t x x)+(x-1).","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131849806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brief announcement: network traffic can optimize consolidation during transformation to virtualization","authors":"Kewei Sun, Ying Li, Jing Luo","doi":"10.1145/1835698.1835764","DOIUrl":"https://doi.org/10.1145/1835698.1835764","url":null,"abstract":"Under the consolidation scenario in Clouds, the network dimension should be considered as important as the computing power of machines. Traditional consolidation procedure is usually made according to the experience, which mainly focused on the hardware capability of the target system, like CPU, Memory and etc. Along with the consolidation of the computing power, the network communication among machines is also consolidated. The consolidation procedure needs to cover this change and avoid network problems after moving the applications into target virtualized system. This paper presents a novel approach to provide optimization taking network traffic into account during consolidation.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132296729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brief announcement: distributed almost stable marriage","authors":"P. Floréen, P. Kaski, V. Polishchuk, J. Suomela","doi":"10.1145/1835698.1835765","DOIUrl":"https://doi.org/10.1145/1835698.1835765","url":null,"abstract":"We study the stable marriage problem in a distributed setting. The communication network is a bipartite graph, with men on one side and women on the other. Acceptable partners are connected by edges, and each participant has chosen a linear order on the adjacent nodes, indicating the matching preferences. The classical Gale-Shapley algorithm could be simulated in such a network to find a stable matching. However, the stable matching problem is inherently global: the worst-case running time of any distributed algorithm is linear in the diameter of the network. Our work shows that if we tolerate a tiny fraction of unstable edges, then a solution can be found by a fast local algorithm: simply truncating a distributed simulation of the Gale-Shapley algorithm is sufficient. Among others, this shows that an almost stable matching can be maintained efficiently in a very large network that undergoes frequent changes.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133366960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brief announcement: modelling MapReduce for optimal execution in the cloud","authors":"Alexander Wieder, Pramod Bhatotia, Ansley Post, R. Rodrigues","doi":"10.1145/1835698.1835795","DOIUrl":"https://doi.org/10.1145/1835698.1835795","url":null,"abstract":"We describe a model for MapReduce computations that can be used to optimize the increasingly complex choice of resources that cloud customers purchase.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133878862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finding mobile data under delay constraints with searching costs","authors":"A. Bar-Noy, Panagiotis Cheilaris, Yi Feng, Asaf Levin","doi":"10.1145/1835698.1835774","DOIUrl":"https://doi.org/10.1145/1835698.1835774","url":null,"abstract":"A token is hidden in one of several boxes and then the boxes are locked. The probability of placing the token in each of the boxes is known. A searcher is looking for the token by unlocking boxes where each box is associated with an unlocking cost. The searcher conducts its search in rounds and must find the token in a predetermined number of rounds. In each round, the searcher may unlock any set of locked boxes concurrently. The optimization goal is to minimize the expected cost of unlocking boxes until the token is found. The motivation and main application of this game is the task of paging a mobile user (token) who is roaming in a zone of cells (boxes) in a cellular network system. Here, the unlocking costs reflect cell congestions and the placing probabilities represent the likelihood of the user residing in particular cells. Another application is the task of finding some data (token) that may be known to one of the sensors (boxes) of a sensor network. Here, the unlocking costs reflect the energy consumption of querying sensors and the placing probabilities represent the likelihood of the data being found in particular sensors. In general, we call mobile data any entity that has to be searched for. The special case, in which all the boxes have equal unlocking costs has been well studied in recent years and several optimal polynomial time solutions exist. To the best of our knowledge, this paper is the first to study the general problem in which each box may be associated with a different unlocking cost. We first present three special interesting and important cases for which optimal polynomial time algorithms exist: (i) There is no a priori knowledge about the location of the token and therefore all the placing probabilities are the same. (ii) There are no delay constraints so in each round only one box is unlocked. (iii) The token is atypical in the sense that it is more likely to be placed in boxes whose unlocking cost is low. Next, we consider the case of a typical token for which the unlocking cost of any box is proportional to the probability of placing the token in this box. We show that computing the optimal strategy is strongly NP-Hard for any number of unlocking rounds, we provide a PTAS algorithm, and analyze a greedy solution. We propose a natural dynamic programming heuristic that unlocks the boxes in a non-increasing order of the ratio probability over cost. For two rounds, we prove that this strategy is a 1.143-approximation solution for an arbitrary token and a 1.108-approximation for a typical token and that both bounds are tight. For an arbitrary token, we provide a more complicated PTAS","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122497313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distributed data classification in sensor networks","authors":"Ittay Eyal, I. Keidar, R. Rom","doi":"10.1145/1835698.1835738","DOIUrl":"https://doi.org/10.1145/1835698.1835738","url":null,"abstract":"Low overhead analysis of large distributed data sets is necessary for current data centers and for future sensor networks. In such systems, each node holds some data value, e.g., a local sensor read, and a concise picture of the global system state needs to be obtained. In resource-constrained environments like sensor networks, this needs to be done without collecting all the data at any location, i.e., in a distributed, manner. To this end, we define the distributed classification problem, in which numerous interconnected nodes compute a classification of their data, i.e., partition these values into multiple collections, and describe each collection concisely. We present a generic algorithm that solves the distributed classification problem and may be implemented in various topologies, using different classification types. For example, the generic algorithm can be instantiated to classify values according to distance, like the famous k-means classification algorithm. However, the distance criterion is often not sufficient to provide good classification results. We present an instantiation of the generic algorithm that describes the values as a Gaussian Mixture (a set of weighted normal distributions), and uses machine learning tools for classification decisions. Simulations show the robustness and speed of this algorithm. We prove that any implementation of the generic algorithm converges over any connected topology, classification criterion and collection representation, in fully asynchronous settings.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"152 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124179867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brief announcement: view transactions: transactional model with relaxed consistency checks","authors":"Y. Afek, Adam Morrison, Moran Tzafrir","doi":"10.1145/1835698.1835711","DOIUrl":"https://doi.org/10.1145/1835698.1835711","url":null,"abstract":"We present view transactions, a model for relaxed consistency checks in software transactional memory (STM). View transactions always operate on a consistent snapshot of memory but may commit in a different snapshot. They are therefore simpler to reason about, provide opacity and maintain composability. In addition, view transactions avoid many of the overheads associated with previous approaches for relaxing consistency checks. As a result, view transactions outperform the prior approaches by 1.13x to 2x on various benchmarks.","PeriodicalId":447863,"journal":{"name":"Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129658643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}