PartiX: processing XQuery queries over fragmented XML repositories

The data volume of XML repositories and the response time of query processing have become critical issues for many applications, especially for those in the Web. An interesting altenative to improve query processing performance consists in reducing the size of XML databases through fragmentation techniques. However, traditional fragmentation definitions do not directly apply to collections of XML documents. This work formalizes the fragmentation definition for collections of XML documents, and proposes an architecture for XQuery processing on top of fragmented XML data. This architecture was implemented in a system prototype named PartiX, which exploits intra-query parallelism on top ofXQuery-enabled sequential DBMS modules. We have analyzed several experimental settings, and our results showed a performance improvement of up to a 72 scale up factor against centralized databases.