We are building a university website and finding a search solution for it. Our university website has high-traffic because it has faculty of open university so very much students (approximately 1.5 million). Even we use caching for speeding up the website. Anyway, which search engine do you suggest for our situation?
Note: We think Solr, Elasticsearch or Sphinx for now, but also it can be one of the others.
Update: We need a full-text search engine which must be fast, extendable and with the features like query likening and indicating priority support.
Thanks.
It really depends on your use-case, what features you want, and whether you have any experience with any of the technologies. I could paraphrase arguments, but there's a very good discussion here: ElasticSearch, Sphinx, Lucene, Solr, Xapian. Which fits for which usage? that covers the pros and cons of each.
Edit (in response to the question's edit):
Of these technologies I have only used Solr (and SQL), but I've found it to be easy to use and would recommend it. It supports native sharding and replication, which should cover the extendibility issue. It also supports things like joins and field weighting, which I think covers all your needs if I read your requirements correctly.