Research And Implementation Of The Cache System In Distributed Search Engine

The distributed caching is one of the most effective solutions which can enhance the system performance of WWW system and at the same time does not increase the cost of one enterprise. Based on national science and technology projects to support "Key technology research and demonstration of Integrated Risk Guardians". Aim at solving the problems of response speed and search effective in the integrated risk search engine, the thesis research a distributed cache system and is devoted to key technology research such as cooperation of cache and replacement algorithm etc. The integrated risk search engine with distributed cache has been implemented and has achieved very good performance and application. The main achievement is as follows:Firstly, design and implementation of distributed cache system has been completed in accordance with need integrated of risk search engine and characteristics of distributed cache system.Secondly, the thesis has designed the HCC (hotspots cooperative caching) cache cooperation mechanism at the basis of analysis for traditional cache cooperation mechanism and the features of search engine. It has introduced system model, cache structure and management between node and protocol in detail. HCC adopts a architecture with control node and cache node, which make distributed management less Complex. In addition, It eliminate hotspot node through copying the "hotspot" documents to low load node and dispersing load into more spots reasonably. Comparison with other cache cooperation mechanism through theory and test data, the conclusion is that HCC is better than other cache cooperation mechanism on access delay etc.Finally, the thesis has designed a replacement algorithm based on characteristics of size for document, visiting frequency, time interval of visit time and without visiting. Through comparison with test data of other cache replacement algorithm, the conclusion is that it's better than other cache replacement algorithm on byte hit rate and grouping hit rate.