MOMIS Goes Multimedia: WINDSURF and the Case of Top-K Queries

In a scenario with “traditional” and “multimedia” data sources, this position paper discusses the following question: “How can a multimedia local source (e.g., Windsurf) supporting ranking queries be integrated into a mediator system without such capabilities (e.g., MOMIS)?” More precisely, “How to support ranking queries coming from a multimedia local source within a mediator system with a “traditional” query processor based on an SQL-engine?” We first describe a na¨ıve approach for the execution of range and Top-K global queries where the MOMIS query processing method remains substantially unchanged, but, in the case of Top-K queries, it does not guarantee to obtain K results. We then discuss two alternative modalities for allowing MOMIS to return the Top-K best results of a global query.