On Using Histograms as Routing Indexes in Peer-to-Peer Systems

Petrakis, Yannis; Koloniari, Georgia; Pitoura, Evaggelia

doi:10.1007/978-3-540-31838-5_2

Cited by 17 publications

(12 citation statements)

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“…As future work, we are currently extending the proposed algorithms using histogram indices instead of simple bit vectors, following an approach similar to (Petrakis et al, 2004). This allows us to store also informations on the approximate number of matches, which can be very useful for certain applications.…”

Section: Discussionmentioning

confidence: 99%

Peer-to-peer systems for discovering resources in a dynamic grid

2007

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The convergence of the Grid and Peer-to-Peer (P2P) worlds has led to many solutions that try to efficiently solve the problem of resource discovery on Grids. Some of these solutions are extensions of P2P DHT-based networks. We believe that these systems are not flexible enough in case the indexed data are very dynamic, i.e., the values of the resource attributes change very frequently over time. This is a common case for some data managed by typical Grid systems, like CPU loads, queue occupation, etc. Moreover, since common requests for Grid resources may be expressed as multi-attribute range queries, we think that the DHTbased P2P solutions that have been proposed so far with the aim of supporting such type of queries can suffer from poor flexibility and efficiency.In this paper we thus present a couple of P2P systems. Both the systems are based on Routing Indexes, used to efficiently route queries and update messages in the presence of highly variable data. The first system needs the adoption of a tree-shaped overlay network. The second one, which is an evolution of the first, is based on a two-level hierarchical network topology, where tree topologies must only be maintained at the lower level of the hierarchy, i.e., within the various node groups making up the network. The main goal of the second organization is to achieve a simpler maintenance of the overall P2P graph topology, by preserving the good properties of the tree-shaped topology.We discuss the results of extensive simulation tests aimed at assessing the performance and scalability of the proposed approaches, by also studying how the network topologies affect the propagation of query and update messages.

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Section: Discussionmentioning

confidence: 99%

Peer-to-peer systems for discovering resources in a dynamic grid

2007

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“…We are currently extending the proposed algorithms using histogram indexes instead of bit vectors, following an approach similar to [10]. This allows us to store also informations on the approximate number of matches, which can be very useful for certain applications.…”

Section: Discussionmentioning

confidence: 99%

Tree vector indexes: efficient range queries for dynamic content on peer-to-peer networks

Marzolla

Mordacchini

Orlando

2006

14th Euromicro International Conference on Parallel, Distributed, and Network-Based Processing (PDP'06)

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“…Crespo et al [5] introduced the notion of routing indexes in P2P systems as structures that, given a query, return a list of inter-esting neighbours (sources) based on a data structure conforming to lists of counts for keyword occurrences in documents. Based on this work, other variants of routing indexes have been proposed, e.g., based on one-dimensional histograms [22], Bloom Filters [23], bit vectors [19], or the QTree. A common feature across these systems is to use a hash function to map string data to a numerical data space.…”

Section: Related Workmentioning

confidence: 99%

Data summaries for on-demand queries over linked data

Harth

Hose

Karnstedt

et al. 2010

Proceedings of the 19th International Conference on World Wide Web

156

155

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Typical approaches for querying structured Web Data collect (crawl) and pre-process (index) large amounts of data in a central data repository before allowing for query answering. However, this time-consuming pre-processing phase however leverages the benefits of Linked Data -where structured data is accessible live and up-to-date at distributed Web resources that may change constantly -only to a limited degree, as query results can never be current. An ideal query answering system for Linked Data should return current answers in a reasonable amount of time, even on corpora as large as the Web. Query processors evaluating queries directly on the live sources require knowledge of the contents of data sources. In this paper, we develop and evaluate an approximate index structure summarising graph-structured content of sources adhering to Linked Data principles, provide an algorithm for answering conjunctive queries over Linked Data on the Web exploiting the source summary, and evaluate the system using synthetically generated queries. The experimental results show that our lightweight index structure enables complete and up-to-date query results over Linked Data, while keeping the overhead for querying low and providing a satisfying source ranking at no additional cost.

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On Using Histograms as Routing Indexes in Peer-to-Peer Systems

Cited by 17 publications

References 12 publications

Peer-to-peer systems for discovering resources in a dynamic grid

Peer-to-peer systems for discovering resources in a dynamic grid

Tree vector indexes: efficient range queries for dynamic content on peer-to-peer networks

Data summaries for on-demand queries over linked data

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