Design and Implementation of a Parallel Processing Scheme for Complex Object Index

点击翻译按钮获取中文摘要

In this research, we have studied parallel indexing schemes for complex objects. The following major contributions have been made.(1) Horizontal and vertical index splitting schemes are proposed, and parallel index retrieval methods are presented and evaluated.2) Parallel index system with online modification capability is proposed and evaluated.(3) A parallel index retrieval scheme is provided and implemented for complex queries combined by AND, OR, NOT logical operators.A fundamental problem on retrieval performance is recognized in the process of constructing above prototype systems. That is, many data packets of low filling up ratio are produced and the communication cost among the related processors much increases. Against this problem, we have invented a scheme of merging more than one packets into a single packet. The scheme incorporates increasing the filling up ratio of packets and effective parallel retrieval termination detecting mechanism. But it was recognized that the scheme suffers from the following drawbacks. That is, a retrieval request may be outrun by the one issued later due to the assumed asynchronous parallel retrieving environment. To incorporate an efficient termination detection scheme, the filling up ratio would be inevitably decreased and the average turnaround time would be increased due to the increase of the communication cost. Against this problem, we have proposed a implementation scheme in which the outrunning of the retrieval requests never occur by scheduling and activating a different set of machines for a new request.We have constructed a parallel index retrieval system that incorporate the scheme and evaluated its performance.