Implementing data cubes efficiently
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Foundations of algorithms using C++ pseudocode (2nd ed.)
Foundations of algorithms using C++ pseudocode (2nd ed.)
Your mediators need data conversion!
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
Capability based mediation in TSIMMIS
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
Operating System Concepts, 4th Ed.
Operating System Concepts, 4th Ed.
Optimizing Queries with Materialized Views
ICDE '95 Proceedings of the Eleventh International Conference on Data Engineering
Don't Scrap It, Wrap It! A Wrapper Architecture for Legacy Data Sources
VLDB '97 Proceedings of the 23rd International Conference on Very Large Data Bases
Querying Heterogeneous Information Sources Using Source Descriptions
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Query Modification in Object-Oriented Database Federations
COOPIS '97 Proceedings of the Second IFCIS International Conference on Cooperative Information Systems
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A global query in a mediator system to integrate distributed information is transformed into a set of its sub-queries and each sub-query is the unit of evaluation in a remote server. Therefore, it is possible to speed up the execution of a global query if the previous results of frequently evaluated sub-queries are materialized in a mediator. Since the integration schema of a mediator can be incrementally modified and the evaluation frequency of a global query can also be continuously varied, query usage should be carefully monitored to determine the optimized set of materialized sub-queries. Furthermore, as the number of sub-queries increases, the optimization process itself may take too long, so that the optimized set identified by a long optimization process may become obsolete due to the recent change of query usage. This paper proposes the adaptive selection of materialized sub-queries such that available storage in a mediator can be highly utilized at any time. In order to differentiate the recent usage of a query from the past, the accumulated usage frequency of a query decays as time goes by. As a result, it is possible to change the set of materialized sub-queries adaptively according to the recent variation of query usage.