Wave-Indices: Indexing Evolving Databases

Abstract

In many applications, new data is being generated every day. Often an index of the data of a past window of days is required to answer queries effciently. For example, in a warehouse one may need an index on the sales records of the last week for effcient data mining, or in a Web service one may provide an index of Netnews articles of the past month. In this paper, we propose a variety of wave indices where the data of a new day can be effciently added, and old data can be quickly expired, to maintain the required window. We compare these schemes based on several system performance measures, such as storage, query response time, and maintenance work, as well as on their simplicity and ease of coding. Keywords: Indexing, sliding windows, temporal databases Note to Referees: This paper is an extended version of a prior conference publication in ACM SIGMOD'97 with the same title. The material has been extended significantly.