5 Search engine is a very cool stuff, recently looked at Lucene, feeling pretty good, in fact, PHP can also make a search engine, the following is the popular open source php search engine.
RiSearch PHP is a high performance, powerful search engine, especially suitable for small and medium-sized site. RiSearch PHP is very fast, it can search 5000-10000 pages in less than 1 seconds. RiSearch is a search engine index, which means it first so your site index and establish a number according to the keyword database to store all your website pages for quick search of the. Risearch is a full-text search engine script, it put all the words are indexed in a single document in addition to define the key words of the configuration files excluded. RiSearch using classic reverse indexing algorithm (with the same large search engine), which is why it will be faster than any other search engine.