%0 Journal Article %J IEEE Data Engineering Bulletin %D 2000 %T Adaptive query processing: Technology in evolution %A Hellerstein,J. M %A Franklin,M.J. %A Chandrasekaran,S. %A Deshpande, Amol %A Hildrum,K. %A Madden,S. %A Raman,V. %A Shah,M. A %X As query engines are scaled and federated, they must cope with highly unpredictable and changeableenvironments. In the Telegraph project, we are attempting to architect and implement a continuously adaptive query engine suitable for global-area systems, massive parallelism, and sensor networks. To set the stage for our research, we present a survey of prior work on adaptive query processing, focusing on three characterizations of adaptivity: the frequency of adaptivity, the effects of adaptivity, and the extent of adaptivity. Given this survey, we sketch directions for research in the Telegraph project. %B IEEE Data Engineering Bulletin %V 23 %P 7 - 18 %8 2000/// %G eng %N 2