Scalable View Expansion in a Peer Mediator System

To integrate many data sources we use a peer mediator framework where views defined in the peers are logically composed in terms of each other. A common approach to execute queries over mediators is to treat views in data sources as ’black boxes’. The mediators locally decompose queries into query fragments and submit them to the data sources for processing. Another approach, used in distributed DBMSs, is to treat the views as ’transparent boxes’ by importing and fully expanding all views and merge them with the query. The black box approach often leads to inefficient query plans. However, in a peer mediator framework full view expansion (VE) leads to prohibitively long query compilation times when many peers are involved. It also limits peer autonomy since peers must reveal their view definitions. We investigate in a peer mediator framework the tradeoffs between none, partial, and full VE in two different distributed view composition scenarios. We show that it is often favo...

• Type: Conference
• Year: 2003
• Where: DASFAA
• Authors: Timour Katchaounov, Vanja Josifovski, Tore Risch
• Keywords: DASFAA 2003, Data Sources, Database, Peer Mediator Framework, Query Compilation Time