An Optimal Cache for a Federated Database System

Federated database systems allow users to query different autonomousdatabases with a single request. The answer to those requests mustbe found on the underlying databases. This answering process can beimproved if some data are cached within the federated databasesystem. The article presents an approach that allows the definitionof an optimal cache for a federated database system according to aset of parameters. We show the types of objects to be cached, thecost model used to decide which ones are worth caching and the methodto find the optimal set of objects to cache. Moreover, this approachcontinuously updates the set of parameter values and periodicallyredefines the optimal cache in order to reflect changes in the userrequirements or in the implementation features of the underlyingdatabases. The article also presents how cached data can be used toanswer a user query. Furthermore, the advantages of using a KnowledgeRepresentation System based on Description Logics in order to definean optimal cache for a federated database system are shown throughthe paper.

[1]  Christine Collet,et al.  Resource integration using a large knowledge base in Carnot , 1991, Computer.

[2]  Craig A. Knoblock,et al.  Intelligent caching: selecting, representing, and reusing data in an information server , 1994, CIKM '94.

[3]  Werner Nutt,et al.  Subsumption between queries to object-oriented databases , 1994, Inf. Syst..

[4]  Divesh Srivastava,et al.  Data model and query evaluation in global information systems , 1995, Journal of Intelligent Information Systems.

[5]  Nick Roussopoulos,et al.  View indexing in relational databases , 1982, TODS.

[6]  Ahmed K. Elmagarmid,et al.  Object orientation in multidatabase systems , 1995, CSUR.

[7]  Miron Livny,et al.  Data caching tradeoffs in client-server DBMS architectures , 1991, SIGMOD '91.

[8]  Elisa Bertino,et al.  Integration of heterogeneous database applications through an object-oriented interface , 1989, Inf. Syst..

[9]  Arthur M. Keller,et al.  A predicate-based caching scheme for client-server database architectures , 1994, Proceedings of 3rd International Conference on Parallel and Distributed Information Systems.

[10]  Arantza Illarramendi,et al.  Building a Federated Relational Database System: An Approach Using a Knowledge-Based System , 1994, Int. J. Cooperative Inf. Syst..

[11]  A. Illarramendi.  Connecting Knowledge Bases with Databases: A complete mapping relation , 1995 .

[12]  James A. Larson,et al.  A Theory of Attribute Equivalence in Databases with Application to Schema Integration , 1989, IEEE Trans. Software Eng..

[13]  Klaus Schild,et al.  A Correspondence Theory for Terminological Logics: Preliminary Report , 1991, IJCAI.

[14]  Bogdan D. Czejdo,et al.  Integration of database systems using an object-oriented approach , 1991, [1991] Proceedings. First International Workshop on Interoperability in Multidatabase Systems.

[15]  Rafael Alonso,et al.  Data caching issues in an information retrieval system , 1990, TODS.

[16]  Weimin Du,et al.  Reducing multidatabase query response time by tree balancing , 1995, SIGMOD '95.

[17]  Albrecht Schmiedel,et al.  The BACK System Revisited , 1989 .

[18]  S. B. Yao,et al.  Optimization Algorithms for Distributed Queries , 1986, IEEE Transactions on Software Engineering.

[19]  Inderpal Singh Mumick,et al.  Selection of views to materialize in a data warehouse , 1997, IEEE Transactions on Knowledge and Data Engineering.

[20]  Weimin Du,et al.  Query Optimization in a Heterogeneous DBMS , 1992, VLDB.

[21]  Michael Stonebraker,et al.  On rules, procedure, caching and views in data base systems , 1990, SIGMOD '90.

[22]  Nick Roussopoulos.  The Logical Access Path Schema of a Database , 1982, IEEE Transactions on Software Engineering.

[23]  Rangasami L. Kashyap,et al.  A Self-Organizing Knowledge Representation Scheme for Extensible Heterogenous Information Environment , 1992, IEEE Trans. Knowl. Data Eng..

[24]  Nick Roussopoulos,et al.  Performance Comparison of Three Modern DBMS Architectures , 1993, IEEE Trans. Software Eng..

[25]  Deborah L. McGuinness,et al.  CLASSIC: a structural data model for objects , 1989, SIGMOD '89.

[26]  J CareyMichael,et al.  Data caching tradeoffs in client-server DBMS architectures , 1991 .

[27]  Stefano Ceri,et al.  Distributed Databases: Principles and Systems , 1984 .

[28]  K. Selçuk Candan,et al.  Query caching and optimization in distributed mediator systems , 1996, SIGMOD '96.

[29]  Craig A. Knoblock,et al.  Retrieving and Integrating Data from Multiple Information Sources , 1993, Int. J. Cooperative Inf. Syst..

[30]  David A. Bell,et al.  Distributed database systems , 1992 .

[31]  Beng Chin Ooi,et al.  On global multidatabase query optimization , 1992, SGMD.

[32]  Timos K. Sellis.  Efficiently supporting procedures in relational database systems , 1987, SIGMOD '87.

[34]  Stefano Spaccapietra,et al.  Model independent assertions for integration of heterogeneous schemas , 1992, The VLDB Journal.

[35]  Jennifer Widom,et al.  The TSIMMIS Project: Integration of Heterogeneous Information Sources , 1994, IPSJ.

[36]  Wei-Min Shen,et al.  Using Carnot for enterprise information integration , 1993, [1993] Proceedings of the Second International Conference on Parallel and Distributed Information Systems.

[37]  Weimin Du,et al.  The Pegasus heterogeneous multidatabase system , 1991, Computer.

[38]  Jeffrey D. Ullman,et al.  Answering Queries Using Limited External Query Processors , 1999, J. Comput. Syst. Sci..

[39]  Jeffrey D. Ullman,et al.  Answering queries using limited external query processors (extended abstract) , 1996, PODS.

[40]  Umeshwar Dayal,et al.  Query Processing in a Multidatabase System , 1985, Query Processing in Database Systems.

[41]  Amit P. Sheth,et al.  On Automatic Reasoning for Schema Integration , 1993, Int. J. Cooperative Inf. Syst..

[42]  W. Alex Gray,et al.  Association Merging in a Schema Meta-Integration System for a Heterogeneous Object-Oriented Database Environment , 1992, BNCOD.

[43]  Sartaj Sahni,et al.  Approximate Algorithms for the 0/1 Knapsack Problem , 1975, JACM.