Academia.eduAcademia.edu

Outline

Title
Abstract
Introduction
P2P Systems and Database Systems
Discussion
Case Studies in P2P Data Sharing Systems
Unstructured P2P Data Sharing Systems
Structured P2P Data Sharing Systems
Super-Peer P2P Data Sharing Systems
Conclusion
References
All Topics
Computer Science
Database Systems

Query Routing and Processing in Peer-To-Peer Data Sharing Systems

Profile image of Raddad al KingRaddad al King

2010

https://doi.org/10.5121/IJDMS.2010.2208
visibility

…

description

24 pages

link

1 file

Abstract

Sharing musical files via the Internet was the essential motivation of early P2P systems. Despite of the great success of the P2P file sharing systems, these systems support only "simple" queries. The focus in such systems is how to carry out an efficient query routing in order to find the nodes storing a desired file. Recently, several research works have been made to extend P2P systems to be able to share data having a fine granularity (i.e. atomic attribute) and to process queries written with a highly expressive language (i.e. SQL). These works have led to the emergence of P2P data sharing systems that represent a new generation of P2P systems and, on the other hand, a next stage in a long period of the database research area. ? The characteristics of P2P systems (e.g. large-scale, node autonomy and instability) make impractical to have a global catalog that represents often an essential component in traditional database systems. Usually, such a catalog stores informat...

Related papers

A Survey of Data Management in Peer-to-Peer Systems
ROLANDO BLANCO

2006

View PDFchevron_right
Distributed Query Processing in {P2P} Systems with Incomplete Schema Information
Kai-Uwe Sattler

The peer-to-peer (P2P) paradigm has emerged recently, mainly by file sharing systems like Napster or Gnutella and in terms of scalable distributed data structures. Because of the decentralization P2P systems promise an improved scalability and robustness, and they open a new view on data integration approaches, too. By exploiting already available mappings between pairs of peers a new peer joining the systems can immediately participate and access all the available data after establishing a correspondence mapping to at least one other peer. One of the technical challenges in building scalable P2P based integration systems is the efficient processing of queries which is complicated by the locally restricted knowledge about data placement and schema information. In this paper, we address this problem by investigating query processing strategies dealing with incomplete schemas and present results of our experimental evaluation.

View PDFchevron_right
PSON: A Scalable Peer-to-Peer File Sharing System Supporting Complex Queries
jyoti ahuja

In this work, we design a P2P file sharing system called PSON to address the important issues of scalability, routing efficiency and complex query support. We propose a semantic overlay network of logical nodes, in which queries are routed on the basis of semantics. A logical node is formed by a cluster of peers that are close to each other in the physical network. Each cluster selects a powerful peer as super peer to support routing in the overlay network. All the super peers are organized in the form of a balanced tree. By exploiting the concepts of hierarchy and semantics, PSON can support complex queries in a scalable and efficient way. We conduct extensive simulations and the results show the promising performance of PSON.

View PDFchevron_right
Enabling flexible queries with guarantees in P2P systems
Manish Parashar

2004

The Squid peer-to-peer information discovery system supports flexible queries using partial keywords, wildcards, and ranges. It is built on a structured overlay and uses data lookup protocols to guarantee that all existing data elements that match a query are found efficiently. Its main innovation is a dimension-reducing indexing scheme that effectively maps multidimensional information space to physical peers.

View PDFchevron_right
Enhancing P2P File-Sharing with an Internet-Scale Query Processor
Ion Stoica

Proceedings 2004 VLDB Conference, 2004

In this paper, we address the problem of designing a scalable, accurate query processor for peerto-peer filesharing and similar distributed keyword search systems. Using a globally-distributed monitoring infrastructure, we perform an extensive study of the Gnutella filesharing network, characterizing its topology, data and query workloads. We observe that Gnutella's query processing approach performs well for popular content, but quite poorly for rare items with few replicas. We then consider an alternate approach based on Distributed Hash Tables (DHTs). We describe our implementation of PIERSearch, a DHT-based system, and propose a hybrid system where Gnutella is used to locate popular items, and PIERSearch for handling rare items. We develop an analytical model of the two approaches, and use it in concert with our Gnutella traces to study the tradeoff between query recall and system overhead of the hybrid system. We evaluate a variety of localized schemes for identifying items that are rare and worth handling via the DHT. Lastly, we show in a live deployment on fifty nodes on two continents that it nicely complements Gnutella in its ability to handle rare items.

View PDFchevron_right
A Model for Data Management in Peer-to-Peer Systems
Francis Otto

2007

Hope University, UK _____________________________________________________________ With the current growth in Peer-to-Peer (P2P) computing, data management in P2P systems has become a very important issue, yet from literature little research effort has been dedicated to this field. Data management in P2P systems covers a wide range of issues starting from storage and indexing, replication and search to security and privacy. In this paper we propose a modularized data management model for P2P systems that cleanly separates the functional components, enabling the implementation of various P2P services with specific quality of service requirements using a common infrastructure besides improving the data management in the P2P system. We present the potential applications that could exploit the advantages our model provides.

View PDFchevron_right
Scalable Peer-to-Peer File Sharing with Efficient Complex Query Support
jyoti ahuja

2007

A good P2P file sharing system is usually expected to achieve the following design goals: scalability, routing efficiency and complex query support. In this paper, we propose such a system, called PSON, which can satisfy all the three requirements. PSON is essentially a semantic overlay network of logical nodes, in which queries are routed on the basis of semantics. A logical node is formed by a cluster of peers that are close to each other in the physical network. Each cluster selects a powerful peer as super peer to support routing in the overlay network. To facilitate routing, all the super peers (or logical nodes) are organized in the form of a balanced tree. By exploiting the concepts of hierarchy and semantics, PSON can support complex queries in a scalable and efficient way. In this paper, we will describe the system architecture, and examine the key component of PSON design, i.e., semantic overlay construction and routing. We also conduct simulations, and show that the query routing in PSON is very efficient (O(log(n)) in the case of exact query) .

View PDFchevron_right
Querying structured data in an unstructured P2P system
Verena Kantere

Proceedings of the 6th Annual Acm International Workshop on Web Information and Data Management, 2004

Peer-to-Peer networking has become a major research topic over the last few years. Sharing of structured data in such decentralized environments is a challenging problem, especially in the absence of a global schema. The standard practice of answering a query that is consecutively rewritten along the propagation path often results in significant loss of information. In this paper, we present an adaptive and bandwidth-efficient solution to the problem in the context of an unstructured, purely decentralized system. Our method allows peers to individually choose which rewritten version of a query to answer and discover information-rich sources left hidden otherwise. Utilizing normal query traffic only, we describe how efficient query routing and clustering of peers can be used to produce high quality answers. Simulation results show that our technique is both effective and bandwidth-efficient in a variety of workloads and network sizes.

View PDFchevron_right
Data Management in P2P Systems
Ana Carolina Salgado

2006

Peer-to-Peer (P2P) systems are massively distributed and highly volatile systems for sharing large amounts of resources. In these systems, peers communicate through a self-organizing and fault tolerant network topology which runs as an overlay on the top of a physical network. Initially developed to allow the sharing of unstructured data (e.g. music and video), recently the proposed P2P systems attempt to provide support for sharing structured and semi-structured data. In general, there are some data management issues that must be addressed when dealing with the scale and volatility of P2P systems: schema mapping, query processing and connection management. In this tutorial we discuss the main solutions that have been proposed to address these important data management issues in P2P systems.

View PDFchevron_right
Information Integration In Schema-Based Peer-to-Peer Networks
Martin Wolpers

Advanced Information Systems …, 2010

View PDFchevron_right

References (66)

  1. S. Alaei, M. Ghodsi and M. Toossi, "Skiptree: A new scalable distributed data structure on multidimensional data supporting range-queries", Journal of Computer Communications, V(33), N(1), pp. 73-82, January 2010.
  2. R. Akbarinia and V. Martins. "Data management in the APPA P2P system". Journal of Grid Computing, Vol 5(3), pp. 303-317 , September 2007.
  3. K. Aberer, P. C. Mauroux, A. Datta, Z. Despotovic, M. Hauswirth, M. Punceva and R. Schmidt. "P- Grid: a self-organizing structured P2P system". SIGMOD Rec. 32, 3 (Sep. 2003), pp. 29-33, 2003.
  4. K. Aberer, P. C. Mauroux and M. Hauswirth. "A Framework for Semantic Gossiping". ACM SIGMOD (SIGMOD'02) Record 31(4), pp. 48-53, 2002.
  5. A. Andrzejak and Z. Xu. "Scalable, efficient range queries for grid information services". In Proc. of the IEEE Int. Conf. on P2P computing, pp : 33-40, 2002.
  6. R. Blanco, N. Ahmed, D. Hadaller, L.G.A. Sung, H. Li and M.A. Soliman. "A survey of data management in peer-to-peer systems". Technical Report CS-2006-18, University of Waterloo, 2006.
  7. A. Bonifati, E. Chang, T. Ho, L. V. Lakshmanan, R. Pottinger and Y. Chung, "Schema mapping and query translation in heterogeneous P2P XML databases". The VLDB Journal, V(19), N(2), pp. 231-256, April 2010.
  8. A. Bonifati, P. K. Chrysanthis, A. M. Ouksel and K. U. Sattler. "Distributed databases and Peer-to-Peer Databases: Past and Present". SIGMOD Rec. 37, 1, pp. 5-11, March 2008.
  9. I. Brunkhorst1, H. Dhraief, A. Kemper, W. Nejdl and C. Wiesner. "Distributed Queries and Query Optimization in Schema-Based P2P-Systems". In Proc. of the Int. Workshop on Databases, Information Systems, and Peer-to-Peer Computing (DISP2P'03), pp. 184-199, 2003.
  10. P. Boncz and C. Treijtel. "AmbientDB: Relational Query Processing in a P2P Network". Int. Workshop on Databases, Information Systems and Peer-to-Peer Computing (DBISP2P), 2003.
  11. A. Crainiceanu, P. Linga, A. Machanavajjhala, J. Gehrke and J. Shanmugasundaram. "P-ring: an efficient and robust P2P range index structure". In Proc. of the 2007 ACM SIGMOD int. Conf. on Management of Data (SIGMOD '07), pp : 223-234, 2007.
  12. A. Crespo, and H. G. Molina. "Routing indices for peer-to-peer systems". IEEE Int. Conf. on Distributed Computing Systems" (ICDCS'02), pp : 23-33, 2002.
  13. M. Cannataro, D. Talia, G. Tradigo, P. Trunfio and P. Veltri, "SIGMCC: A system for sharing meta patient records in a Peer-to-Peer environment". Journal of Future Generation Computer Systems, V(24), N(3), pp.222-234, March 2008.
  14. N. Daswani, H. G. Molina and B. Yang. "Open problems in data-sharing peer-to-peer systems". Int. Conf. on Database Theory (ICDT'03), pp. 1-15, 2003.
  15. E. Franconi, G. Kuper, A. Lopatenko, I. Zaiharayeu, "Queries and Updates in the coDB Peer to Peer Database System", in the proceedings of the 30th VLDB, pp. 1277-1280, 2004.
  16. A. Gupta, D. Agrawal and A. El Abbadi. "Approximate range selection queries in peer-to-peer systems". First Biennial Conference on Innovative Data Systems Research (CIDR'03), pp. 141-151, 2003.
  17. S. Girdzijauskas, A., Datta and K. Aberer, "Structured overlay for heterogeneous environments: Design and evaluation of oscar". ACM Trans. Auton. Adapt. Syst. 5, 1, pp. 1-25, 2010.
  18. F. Giunchiglia and I. Zaihrayeu. "Implementing Database Coordination in P2P Networks". The Second Workshop on Semantics in Peer-to-Peer and Grid Computing (SemPGrid'04), 2004.
  19. Halevy, A. "Why Your Data Won't Mix: Semantic Heterogeneity". ACM Queue 3(8), pp. 50-58, 2005.
  20. R. Huebsch, B. Chun, J. M. Hellerstein, B. T. Loo, P. Maniatis, T. Roscoe, S. Shenker, I. Stoica and A. R. Yumerefendi. "The Architecture of PIER: an Internet-Scale Query Processor". In Proc. of the 2005 CIDR Conf. pp : 28-43, 2005.
  21. M. Harren, J.M. Hellerstein, R. Huebsch, B.T. Loo, S. Shenker and I. Stoica. "Complex queries in DHT-based peer-to-peer networks". Int. Workshop on Peerto-Peer Systems (IPTPS'02), pp. 242-259, 2002.
  22. A. Halevy, Z. Ives, P. Mork and I. Tatarinov. "Piazza: data management infrastructure for semantic web applications". Int. Conf. on World Wide Web (WWW'03), pp : 556-567, 2003.
  23. A. Ismail, M., Quafafou, G., Nachouki, and M. Hajjar, "Efficient super-peer-based queries routing". MEDES '09. ACM, pp. 91-98, 2009.
  24. A. Ismail, M. Quafafou, G. Nachouki and M. Hajjar, "Data mining effect in peer-to-peer queries routing". In Proceedings of the International Conference on Management of Emergent Digital Ecosystems (MEDES '09), ACM, pp.65-72, 2009.
  25. Y. Joung and F. Chuang, "OntoZilla: An ontology-based, semi-structured, and evolutionary peer-to-peer network for information systems and services". Journal of Future Generation Computer Systems, V(25), N(1), pp. 53-63, January 2009.
  26. H.V. Jagadish, B. C. Ooi and Q. H. Vu. "BATON: A Balanced Tree Structure for Peer-to-Peer Networks". VLDB'05, pp. 661-672, 2005.
  27. F. B.Kashani and C. Shahabi, "Fixed-Precision Approximate Continuous Aggregate Queries in Peer-to- Peer Databases," icde, pp.1427-1429, 2008 IEEE 24th International Conference on Data Engineering, 2008
  28. V. Kalogeraki, D. Gunopulos, and D. Zeinalipour-Yazti, "A local search mechanism for peer-to-peer networks". In Proceedings of the CIKM '02. ACM, pp. 300-307, 2002.
  29. R. A. King, A. Hameurlain and F. Morvan. "Metadata Lookup for Distributed Query Optimization in P2P Environment". PDCS'07, ISCA, pp. 36-43, 2007.
  30. R. A. King, A. Hameurlain and F. Morvan. "Ontology-Based Data Source Localization in a Structured Peer-to-Peer Environment". IDEAS'08, pp. 9-18, 2008.
  31. R. A. King, A. Hameurlain and F. Morvan. "Ontology-Based Method for Schema Matching in Peer-to- Peer Database System". BNCOD'9 (poster session), pp. 208-212, 2009.
  32. R. A. King, A. Hameurlain and F. Morvan. "Matching Heterogeneous Schemas in a Large-Scale Peer- to-Peer Database Environment". PDCCS'09, ISCA, pp. 135-142, 2009.
  33. G. Koloniari and E. Pitoura. "Peer-to-peer Management of XML Data: Issues and Research Challenges". SIGMOD Record, 34(2), pp.6-17, 2005.
  34. D. Kossmann, "The state of the art in distributed query processing", ACM Comput. Surv. 32, 4 (Dec. 2000), pp. 422-469, 2000.
  35. V. Kantere, D. Tsoumakos, T. Sellis and N. Roussopoulos "GrouPeer: Dynamic clustering of P2P databases". Journal of Information Systems. V(34), N(1), pp. 62-86, March 2009.
  36. M. Lenzerini, "Data Integration: A Theoretical Perspective", Proceedings of the Twenty-first ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, pp. 233-246, 2002.
  37. A.Y. Levy, A. Rajaraman and J. J. Ordille. "Querying Heterogeneous Information Sources Using Source Descriptions", In Proceedings of 22nd VLDB, pp. 251-262, 1996.
  38. M. Masud and M. A. Hossain, "Dynamic Query Plan for Efficient Query Processing in Peer-to-Peer Environments", INFOCOMP Journal of Computer Science, Vol.7 (3). pp.01-06, 2008
  39. V. Martins, R. Akbarinia, E. Pacitti and P. Valduriez. "Reconciliation in the APPA P2P system". IEEE Int. Conf. on Parallel and Distributed Systems (ICPADS'06), pp. 401-410, 2006.
  40. D. S. Milojicic, V. Kalogeraki, R. Lukose, K. Nagaraja, J. Pruyne, B. Richard, S. Rollins and Z. Xu. "Peer-to-Peer Computing". Tech. Report: HPL-2002-57, available on line at: http://www.hpl.hp.com/techreports/2002/HPL-2002-57.pdf
  41. H. G. Molina, Y. Papakonstantinou, D. Quass, A. Rajaraman, Y. Sagiv, J. Ullman and J. Widom. "The TSIMMIS project: Integration of heterogeneous information sources". Journal of Intelligent Information Systems, 8(2), March 1997.
  42. W. S. Ng, B. C. Ooi, K. L. Tan and A. Zhou. "PeerDB: a P2P-based system for distributed data sharing". Int. Conf. on Data Engineering (ICDE'03), pp : 633-644, 2003.
  43. W. Nejdl, B. Wolf, C. Qu, S. Decker, M. Sintek, A. Naeve, M. Nilsson, M. Palmer, and T. Risch. "Edutella: a P2P networking infrastructure based on RDF". Int. Conf. on World Wide Web (WWW'02), pp. 604-615, 2002.
  44. B. C. Ooi, Y. Shu and K. L. Tan. "Relational Data Sharing in Peer-based Data Management Systems". ACM SIGMOD, 23 (3), pp : 59-64, 2003.
  45. M.T. Ozsu and P. Valduriez. "Principles of Distributed Database Systems". Prentice Hall ISBN 0-13- 659707-6, 1999. Second Edition.
  46. V. Papadimos and D. Maier "Mutant Query Plans". In OOPSLA, 2001.
  47. V. Papadimos and D. Maier "Distributed Queries without Distributed State". In WebDB, 2002.
  48. S. Ratnasamy, P. Francis, M. Handley, R. Karp and S. Shenker. "A scalable content-addressable network". ACM SIGCOMM Conf. on Applications, Technologies, Architectures, and Protocols for Computer Communications, pp. 161-172, 2001.
  49. A. Rowstron and P. Druschel. "Pastry: scalable, distributed object location and routing for large-scale peer-to-peer systems". IFIP/ACM Int. Conf. on Distributed Systems Platforms (Middleware), pp. 329- 350, 2001.
  50. C. Roncancio, M. Pilar Villamil, C. Labbé and P. Serrano-Alvarado, "Data Sharing in DHT Based P2P Systems". In Transactions on Large-Scale Data-and Knowledge-Centered Systems I, A. Hameurlain, J. Küng, and R. Wagner, Eds. Lecture Notes In Computer Science, vol. 5740. Springer-Verlag, Berlin, Heidelberg, pp. 327-352, 2009.
  51. P. Shvaiko and J. Euzenat. "A survey of schema-based matching approaches". Journal on Data Semantics. IV. LNCS, vol. 3730, pp. 146-171. Springer, Heidelberg, 2005.
  52. C. Shirky. "What is P2P and What Isn't". The O'Reilly Peer to Peer and Web Service Conf., Washington, D.C. November 5-8, 2001. Available on: http://conferences.oreillynet.com/p2p/.
  53. M. Sínchez-Artigas and P. García-López, "eSciGrid: A P2P-based e-science Grid for scalable and efficient data sharing". Journal of Future Generation Computer Systems, V(26), N(5), pp.704-719, May 2010.
  54. I. Stoica, R. Morris, D.R. Karger, M.F. Kaashoek and H. Balakrishnan. "Chord: a scalable peer-to-peer lookup service for internet applications". ACM Conf. on Applications, Technologies, Architectures, and Protocols for Computer Communications (SIGCOMM'01), pp. 149-160, 2001.
  55. I. Sarr, H. Naacke and S. Gançarski, "TransPeer: adaptive distributed transaction monitoring for Web2.0 applications". In Proceedings of the 2010 ACM Symposium on Applied Computing (SAC '10), ACM, pp. 423-430, 2010.
  56. M. Schlosser, M. Sintek, S. Decker and W. Nejdl. "HyperCuP -Hypercubes, Ontologies and Efficient Search on P2P Networks". International Workshop on Agents and Peer-to-Peer Computing, 2002.
  57. S. A. Theotokis and D. Spinellis. "A survey of peer-to-peer content distribution technologies". ACM Computing Surveys, 36(4), pp. 335-371, 2004.
  58. I. Tatarinov, Z.G. Ives, J. Madhavan, A. Halevy, D. Suciu, N. Dalvi, X. Dong, Y. Kadiyska, G. Miklau and P. Mork. "The Piazza peer data management project". ACM SIGMOD Record, 32(3), pp : 47-52, 2003.
  59. Y. Tao, H. Jin, S. Wu and X. Shi, "Scalable DHT-and ontology-based information service for large- scale grids". Journal of Future Generation Computer Systems, V(26), N(5), pp. 729-739, May 2010.
  60. D. Tsoumakos and N. Roussopoulos. "Adaptive probabilistic search (APS) for peer-to-peer networks". In Proc. of the Int. IEEE Conference on P2P Computing, pp : 102-109, 2003.
  61. P. Valduriez and E. Pacitti, "Data Management in Large-Scale P2P Systems". VECPAR'04, pp. 104- 118, 2004.
  62. M.P. Villamil, C. Roncancio, C. Labbé, "PinS: Peer-to-Peer Interrogation and Indexing System". IDEAS'04, pp. 236-245, 2004.
  63. B. Yang, H. G. Molina. "Improving search in peer-to-peer networks". In Proc. of the IEEE Int. Conf. on Distributed Computing Systems (ICDCS'02), pp. 5-14, 2002.
  64. B. Yang, H. G. Molina. "Comparing Hybrid Peer-to-Peer Systems". VLDB'02, pp. 561-570 2002.
  65. B. Yang and H. G. Molina. "Designing a Super-Peer Network". ICDE'03, 2003.
  66. B.Y. Zhao, L. Huang, J. Stribling, S.C. Rhea, A.D. Joseph and J.D. Kubiatowicz. "Tapestry: a resilient global-scale overlay for service deployment". IEEE Journal on Selected Areas in Communications (JSAC), 22(1), pp : 41-53, 2004.

Related papers

Data Sharing in P2P Systems
Guillaume Raschia

Handbook of Peer-to-Peer Networking, 2009

In this chapter, we survey P2P data sharing systems. All along, we focus on the evolution from simple file-sharing systems, with limited functionalities, to Peer Data Management Systems (PDMS) that support advanced applications with more sophisticated data management techniques. Advanced P2P applications are dealing with semantically rich data (e.g. XML documents, relational tables), using a high-level SQL-like query language. We start our survey with an overview over the existing P2P network architectures, and the associated routing protocols. Then, we discuss data indexing techniques based on their distribution degree and the semantics they can capture from the underlying data. We also discuss schema management techniques which allow integrating heterogeneous data. We conclude by discussing the techniques proposed for processing complex queries (e.g. range and join queries). Complex query facilities are necessary for advanced applications which require a high level of search expressiveness. This last part shows the lack of querying techniques that allow for an approximate query answering.

View PDFchevron_right
Topics in Database Systems: Data Management in Peer-to-Peer Systems Survey of Peer-to-Peer Systems
Vicki Tziovara

Peer-to-peer (P2P) networking has generated tremendous interest worldwide among Internet users as well as computer professionals. P2P systems like Kazaa and Napster rank amongst the most popular software applications ever. P2P systems have become popular Internet applications since the arrival of Napster and other P2P architectures used for music file sharing. Several businesses and Web sites have promoted P2P technology as the future of Internet networking. In recent years, peer-to-peer systems have emerged as an interesting architecture for implementing distributed file systems. In a P2P network, end users share resources which are able to exchange. Information is distributed among the member nodes instead of being concentrated at a single server. A successful P2P file-sharing network must have some desirable properties, such as ease of use, ability to expand over large numbers of peers, produce results despite node failures and find infrequent items. This survey of P2P systems presents different system architectures used for file-sharing and query routing protocols. We discuss more complex queries, such as range queries over one or more attributes and replication techniques. Finally, we refer to algorithms for updating replicas.

View PDFchevron_right
Query Routing and Processing in Schema-Based P2P Systems
Katja Hose

2004

Recently, the peer-to-peer (P2P) paradigm has emerged, mainly by file sharing systems such as Napster and Gnutella and in terms of scalable distributed data structures. Due to the decentralization, P2P systems promise an improved robustness and scalability and therefore open also a new view on data integration solutions. However, several design and technical challenges arise in building scalable P2Pbased integration systems. In this paper, we address one of them: the problem of distributed query processing. We discuss strategies of query decomposition and routing based on different kinds of routing indexes and present results of an experimental evaluation.

View PDFchevron_right
Query Coordination for Distributed Data Sharing in P2P Networks
Maybin Muyeba

2006

Organisations often store information about the same entity objects or features in different formats. Accessing and integrating this distributed information can be a difficult task because of schema differences and database platform issues. In this paper, a discussion on query coordination in schema conflicting databases of Peer-to-Peer (P2P) systems is presented. The coordination mechanism with a global query to resolve the issue is proposed. The coordination mechanism is done without peers knowing each others schemas by translating the global query into the local query according to the under lying database schema while a wrapper is used to deal with database platform issues. The paper simulates a real-life application and shows that schema resolution by a query coordination mechanism in P2P systems is effective and minimises most of the complexities encountered by schema integration systems.

View PDFchevron_right
PSON: A scalable P2P file sharing system with efficient complex query support
jyoti ahuja

Peer-to-peer Networking and Applications, 2011

A desired P2P file sharing system is expected to achieve the following design goals: scalability, routing efficiency and complex query support. In this paper, we propose a powerful P2P file sharing system, PSON, which can satisfy all the three desired properties. PSON is essentially a semantic overlay network of logical nodes. Each logical node represents a cluster of peers that are close to each other. A powerful peer is selected in each cluster to support query routing on the overlay network while the less powerful peers are responsible for the maintenance of shared contents. To facilitate query routing, super peers are organized in form of a balanced binary search tree. By exploiting the concept of semantics, PSON can support complex queries in a scalable and efficient way. In this paper, we present the basic system design such as the semantic overlay construction, query routing and system dynamics. A load balancing scheme is proposed to further enhance the system performance. By simulation experiments, we show that PSON is scalable, efficient and is able to support complex queries.

View PDFchevron_right

Related topics

  • Database Management Systems
  • File Sharing
  • Query Routing
  • Schema Matching
    • 580 California St., Suite 400
    San Francisco, CA, 94104
    © 2025 Academia. All rights reserved