适应性查询处理——Internet数据查询面临的挑战与解决技术

Adaptive Query Processing:Solution for Internet Data Querying

随着基于Internet的数据查询系统的发展与普及,适应性查询处理逐渐成为一项重要的技术。目前的Internet可以看作一个庞大的分布式和异构化数据库,各个数据源具有自治性,加上广域网网络传输带宽的限制,各个数据源数据的可访问性以及传输速度是经常变化和不可预测的。传统的采用“停止-进行”方式的查询处理不能很好地处理这种情况。而能够在查询执行过程中动态调整查询计划的适应性查询处理是针对此类应用的最佳选择。文章论述适应性查询处理涉及的研究课题及解决技术,并例举最新的研究成果。

The growth of data query system based on Internet makes adaptive query processing become a more and more important technology.The current Internet is becoming a huge distributed and heterogeneous database,with each data source being autonomous.Plus the limited data transfer bandwidth,data sources will provide unpredictable data ac-cess and transfer rates.While traditional query processing technology,which proceeds in a'stop-and-go'fashion,cannot cope well with such delays in receiving data,adaptive query processing,which will dynamically optimize query plan dur-ing execution,becomes the best candidate solution for such application.This paper will discuss the research topics and technologies involved in adaptive query processing and list the recent research progress.