A Library Application on Top of an RDBMS: Performance Aspects

Applications which require a combination of structured data with unstructured text elds are becoming of increasing practical interest. But whereas structured data are usually stored in a relational database, large text collections are maintained by proprietary text or information retrieval systems. The synthesis of both areas is still a topic of intensive research. We describe one such application, namely maintaining library catalogues, and study the eeciency of two implementation alternatives both based on RDBMS technology. In the rst alternative word occurrence information is encoded using bitlists. The other chooses a direct implementation within the relational model. Performance tests are done which are based on real world data and real world user transactions. They demonstrate that the problem of the bitlist implementation is caused by conversions which are necessary to combine them with struc-tured data. In contrast, our direct implementation beneets from today's sophisticated RDBMS technology and performs promisingly well.