We believe that relational database are the most researched and best engineered query processing infrastructures available today. They are able to efficiently query tons of data. By using a relational database as runtime environment for an XQuery processor we can port 30+ years of research to the XQuery domain and build a processor that is able to scale well with increasing input sizes.
Pathfinder is a re-targetable query compiler that turns XQuery expressions into table algebra queries. While Pathfinder is tightly coupled with MonetDB we also provide a SQL code generator that allows any database to become a faithful XQuery processor.
Pathfinder assumes a database to store shredded XML documents—documents that are transformed into a relational encoding. An incoming XQuery query is compiled by Pathfinder into a relational query plan. The database evaluates the generated query plan based on the shredded XML documents and returns a table. A serializer consumes this table and transforms it into an XQuery result sequence. (In MonetDB/XQuery automatic shredding and serialization as well as the tight integration of Pathfinder lead to a runtime where the relational approach is not visible for the user anymore.)
- The software is available via the Download page.
- A list of publications around the Pathfinder research project is provided on the Publications page.
- More details and explanations on Pathfinders performance and internals can be found on the Technology page.