in reply to OT: Vector based search engine
If you just want a good efficient seach engine I would recommend Swish-e We use it. So does apache.org and many other open source websites. The index code is in C of course but there is a Perl XS Swish::API module that ships with it. There is also a Perl front end. It is stable free and fast. Under mod perl (which gives you a persistent search object) searching a reasonable sized website it is blindingly fast ie sub millisecond. The result highlighting code takes about 4 times longer to run than the search.