DBMS Technology for the AVO

Database management technology is central to the development of the Virtual Observatory (VObs), since its eventual aim is that the worlds astronomical data collections should look like a single large distributed database. Relational database management systems (DBMS) are good at searching through large tabular datasets such as source catalogues, but the important operation of cross−matching sources in different catalogues is supported only with difficulty. Two algorithms for doing this were examined: that based on a true spatial index was found to be superior. Since relational DBMS are not all that well suited to the requirements of the Vobs, some alternative structures were also examined. An object−relational open−source package, PostgreSQL, appeared to be the most suitable of the DBMS examined.