XRPC: efficient distributed query processing on heterogeneous XQuery engines
Yuyao Zhang · UvA-DARE (University of Amsterdam) · 2010
In Chapter 4, we discuss various uses of XRPC for distributed XQuery processing on heterogeneous XQuery engines.First, by using Saxon, we demonstrate how XRPC can be used already with any XQuery system, using an XRPC wrapper that is capable of translating Bulk RPC requests into XQuery.We also show how XRPC can be used to elegantly express various distributed query processing strategies, including experiments in which MonetDB/XQuery and Saxon work together over XRPC, using e.g. the distributed semi-join strategy.Then, we turn our attention to the interaction between XRPC and XQUF.We first define a deterministic distributed update semantics and show that a small extension to the SOAP XRPC protocol enables the protocol to conform to the deterministic update semantics.We then describe how the industry standard Web Service Atomic Transaction[55] could be adapted to support atomic distributed commits of XQUF queries on heterogeneous XQuery engines.Finally, we discuss our first step towards integrating an XDBMS and DHT-based overlays in MonetDB/XQuery .While XRPC already allows performing P2P queries, it still misses a number of vital P2P functionalities (robust connectivity, peer and resource discovery, approximate query/transaction processing).In Section 4.6, we propose two different ways to couple an XDBMS with DHTs, i.e., a loose-coupling and a tight-coupling.This chapter addresses the research questions 2, 3 and 5, and is based on the following papers (in the order of their appearance):• Y. Zhang, P. A. Boncz.