Although search by keywords is particularly important for resource and service discovery in P2P networks, existing techniques for keyword search in structured P2P overlays suffer from several problems: unbalanced load, hot spots, fault tolerance, storage redundancy, and unable to facilitate ranking and keyword expansion. In this paper, we present a general keyword index and search scheme for structured P2P networks that avoids these problems, and in which object insert, delete, and search can be efficiently performed. Some experimental results are also presented to support our claim.

We address wildcard search in structured peer-to-peer (P2P) networks, which, to our knowledge, has not yet been explored in the literature. We begin by presenting an approach based on some well-known techniques in information retrieval (IR) and discuss why it is not appropriate in a distributed environment. We then present a simple and novel technique to index objects for wildcard search in a fully decentralized manner, along with some search strategies to retrieve objects. Our index scheme, as opposed to a traditional IR approach, can achieve quite balanced loads, avoid hop spots and single point of failure, reduce storage and maintenance costs, and offer some ranking mechanisms for matching objects. We use the compact disc (CD) records collected in FreeDB (http://freedb.org) as the experimental data set to evaluate our scheme. The results confirm that our index scheme is very effective in balancing the load. Moreover, search efficiency depends on the information given in a query: the more the information, the higher the performance.

We present a simple yet novel technique for prefix search in P2P networks. The idea is to extract characters and their position information in a keyword to index objects. Our index scheme can achieve quite balanced loads, avoid hop-spots and single point of failure, reduce storage and maintenance costs, and offer some ranking mechanisms for matching objects. We use 2,412,613 CD records collected in FreeDB (http://freedb.org) as experimental dataset to test our index scheme.

Existing techniques for keyword/attribute search in structured P2P overlays suffer from several problems: unbalanced load, hot spots, fault tolerance, storage redundancy, and unable to facilitate ranking. In this paper, we present a general keyword index and search scheme for structured P2P networks that avoids these problems, and in which object insert, delete, and search can be efficiently performed. Some experimental results are also presented to support our claim.