A Framework for Multilevel Indexing in Search Engines

Indexing in search engines has been an active area of current researches. Granting efficient and fast access to the index is a key issue for performance of Web Search Engines. Search Engines use inverted indexes that consist of an array of posting lists where each posting list is associated with a term and contains the identifiers of the documents containing the term. A global single large size index takes a long time to search the relevant documents in response to the user queries. This paper proposes multilevel indexing i.e. creating the indexes at the multiple levels so as to reduce the search time by directing the search to a specific path from higher level indexes to the lower level indexes. The multilevel indexes are created after the hierarchical clusters of the documents have been formed on the basis of document similarity. At each level of documents clusters hierarchy, a separate index is created and the search for a document proceeds from the higher level indexes to the lowest level index which is the document level index and is stored as inverted file.