XBird/D: Distributed and Parallel XQuery Processing using Remote Proxy

In this paper, we focus on an aspect of distributed XQuery processing that involves data exchanges between processor elements. We first address problems of distributed XML query processing and explain how the problems differ from traditional database problems. Then, in order to achieve efficient and transparent data exchange, we adopt the use of remote proxy, in which each shipped data is wrapped in a proxy sequence, and the proxy sequence is returned to the remote peer. When accessing the proxy sequence, ac-tual results (possibly partial results) are fetched from a data provider, and then the data provider evaluates its entity se-quence in a call-by-need fashion. Our scheme allows parallel query execution and reduces network traffic and redundant buffer utilization by exchanging required data directly be-tween a consumer and a provider