Scalable, flexible and generic instant overview search

The last years there is an increasing interest on providing the top search results while the user types a query letter by letter. In this paper we present and demonstrate a family of instant search applications which apart from showing instantly only the top search results, they can show various other kinds of precomputed aggregated information. This paradigm is more helpful for the end user (in comparison to the classic search-as-you-type), since it can combine autocompletion, search-as-you-type, results clustering, faceted search, entity mining, etc. Furthermore, apart from being helpful for the end user, it is also beneficial for the server's side. However, the instant provision of such services for large number of queries, big amounts of precomputed information, and large number of concurrent users is challenging. We demonstrate how this can be achieved using very modest hardware. Our approach relies on (a) a partitioned trie-based index that exploits the available main memory and disk, and (b) dedicated caching techniques. We report performance results over a server running on a modest personal computer (with 3 GB main memory) that provides instant services for millions of distinct queries and terabytes of precomputed information. Furthermore these services are tolerant to user typos and the word order.